To see the other types of publications on this topic, follow the link: Threshold-based.
Dissertations / Theses on the topic 'Threshold-based'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Threshold-based.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Zheng, Yexin. "Novel RTD-Based Threshold Logic Design and Verification." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32011.
Full textAbstract:
Innovative nano-scale devices have been developed to enhance future circuit design to overcome physical barriers hindering complementary metal-oxide semiconductor (CMOS) technology. Among the emerging nanodevices, resonant tunneling diodes (RTDs) have demonstrated promising electronic features due to their high speed switching capability and functional versatility. Great circuit functionality can be achieved through integrating heterostructure field-effect transistors (HFETs) in conjunction with RTDs to modulate effective negative differential resistance (NDR). However, RTDs are intrinsically suitable for implementing threshold logic rather than Boolean logic which has dominated CMOS technology in the past. To fully take advantage of such emerging nanotechnology, efficient design methodologies and design automation tools for threshold logic therefore become essential.
In this thesis, we first propose novel programmable logic elements (PLEs) implemented in threshold gates (TGs) and multi-threshold threshold gates (MTTGs) by exploring RTD/ HFET monostable-bistable transition logic element (MOBILE) principles. Our three-input PLE can be configured through five control bits to realize all the three-variable logic functions, which is, to the best of our knowledge, the first single RTD-based structure that provides complete logic implementation. It is also a more efficient reconfigurable circuit element than a general look-up table which requires eight configuration bits for three-variable functions. We further extend the design concept to construct a more versatile four-input PLE. A comprehensive comparison of three- and four-input PLEs provides an insightful view of design tradeoffs between performance and area. We present the mathematical proof of PLE's logic completeness based on Shannon Expansion, as well as the HSPICE simulation results of the programmable and primitive RTD/HFET gates that we have designed. An efficient control bit generating algorithm is developed by using a special encoding scheme to implement any given logic function.
In addition, we propose novel techniques of formulating a given threshold logic in conjunctive normal form (CNF) that facilitates efficient SAT-based equivalence checking for threshold logic networks. Three different strategies of CNF generation from threshold logic representations are implemented. Experimental results based on MCNC benchmarks are presented as a complete comparison. Our hybrid algorithm, which takes into account input symmetry as well as input weight order of threshold gates, can efficiently generate CNF formulas in terms of both SAT solving time and CNF generating time.Master of Science
2
Calota, Andra. "Reliability of spasticity measurement based on tonic stretch reflex threshold." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111947.
Full textAbstract:
Studies suggest that deficits in central regulation of stretch reflex thresholds (SRT) underlie both spasticity and other disorders of motor control. We investigated intra- and inter-evaluator reliability to quantify spasticity based on tonic SRT (TSRT) and the relationship between TSRT and Modified Ashworth Scale (MAS, clinical assessment of resistance to stretch). Spasticity was evaluated in 20 subjects with chronic stroke-related spasticity in two different days, by three evaluators. Twenty different velocity-dependent dynamic SRT (angle where biceps brachii EMG signal increased for a given velocity of stretch) were recorded. TSRT (excitability of motoneurons at 0°/sec) was then computed. Spasticity was also estimated with MAS. Reliability was moderately good for subjects with moderately high spasticity (intra--evaluator: 0.46 to 0.68, inter--evaluator: 0.53 to 0.68). There was no correlation between TSRT and MAS since they measure different phenomena. TSRT is a promising new measure of spasticity. Further improvements for its quantification are suggested.
3
Haboush, W. S. "Adaptive task selection using threshold-based techniques in dynamic sensor networks." Thesis, University of Kent, 2008. https://kar.kent.ac.uk/24027/.
Full text
4
Kannamareddy, Aruna Sai. "Density and partition based clustering on massive threshold bounded data sets." Kansas State University, 2017. http://hdl.handle.net/2097/35467.
Full textAbstract:
Master of ScienceDepartment of Computing and Information Sciences
William H. Hsu
The project explores the possibility of increasing efficiency in the clusters formed out of massive data sets which are formed using threshold blocking algorithm. Clusters thus formed are denser and qualitative. Clusters that are formed out of individual clustering algorithms alone, do not necessarily eliminate outliers and the clusters generated can be complex, or improperly distributed over the data set. The threshold blocking algorithm, a current research paper from Michael Higgins of Statistics Department on other hand, in comparison with existing algorithms performs better in forming the dense and distinctive units with predefined threshold. Developing a hybridized algorithm by implementing the existing clustering algorithms to re-cluster these units thus formed is part of this project. Clustering on the seeds thus formed from threshold blocking Algorithm, eases the task of clustering to the existing algorithm by eliminating the overhead of worrying about the outliers. Also, the clusters thus generated are more representative of the whole. Also, since the threshold blocking algorithm is proven to be fast and efficient, we now can predict a lot more decisions from large data sets in less time. Predicting the similar songs from Million Song Data Set using such a hybridized algorithm is considered as the data set for the evaluation of this goal.
5
Whiten, Darren M. (Darren Mark) 1977. "Threshold predictions based on an electro-anatomical model of the cochlear implant." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/87847.
Full textAbstract:
Thesis (S.M. and Elec.E.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (p. 135-141).
by Darren M. Whiten.
S.M.and Elec.E.
6
Zou, Tao. "Non-Destructive Bridge Deck Condition Assessment with a Probability-Based Deterioration Threshold." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/49384.
Full textAbstract:
Deterioration of bridge decks is an ongoing problem faced by transportation agencies across the country. In past decades, Non-Destructive Evaluation (NDE) techniques, capable of detecting various deteriorations types, e.g., cracking, delamination and reinforcing steel corrosion, have emerged. These techniques generate large amounts of data representing different underlying physics, (decibels for ground penetrating radar and volts for half-cell potential), making data interpretation and comparison difficult for bridge owners and practitioners. The deterioration threshold, or the transition between healthy and deteriorated areas, is essential in understanding NDE data. However, this threshold is determined empirically in former research and engineering practice. In the present research, a probability-based method is proposed to identify deterioration thresholds for specified confidence levels. NDE data measuring different underlying physics are transformed into a binary format by threshold values to compare and combine multiple NDE techniques for bridge deck assessment. The finite element method is also implemented to correlate bridge deck surface stresses with deteriorations measured by NDE techniques, and to study the causes on concrete bridge deck degradation. The general methodology developed in this study will be demonstrated on three bridges, i.e., Virginia, New Jersey and New York Pilot Bridges, which were studied under Federal Highway Administration (FHWA)'s Long-Term Bridge Performance (LTBP) Program.Ph. D.
7
Dickinson, James Edwin. "A ground based gamma ray telescope of high sensitivity and low energy threshold." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5279/.
Full textAbstract:
The subject of this thesis is ground based gamma ray astronomy using the atmospheric Cerenkov technique. Chapter 1 defines the gamma ray region of the electromagnetic spectrum, introduces celestial gamma rays as a component of the flux of energetic particles known as cosmic rays and considers the physical mechanisms by which celestial gamma rays may be produced and absorbed. The phenomenon of Cerenkov radiation, and Its production within the extensive air showers which result from the Interaction of energetic cosmic rays with the atmosphere. Is the subject of Chapter 2. Chapter 3 introduces the early Durham telescopes, and considers the possible improvement to instrument sensitivity afforded by invokatlon of more sophisticated background rejection strategies. The Mk.5 telescope, which is the subject of Chapter 4, Is the vehicle by which the Durham group has sought to assess the relative merits of various signal enhancement strategies, and prove the viability of a design for a high resolution Imaging detector with the additional capacity to make observations at very low energies; the Mk.6 telescope. Chapter 5 introduces a novel concept of background rejection based upon the stereoscopic Imaging of extensive air showers, and describes modifications to the Mk.3 necessary to provide a complement to the Mk.5 in this capacity. Chapter 6 presents the analysis of a burst of periodic gamma ray emission from AE Aquarii, which demonstrates the efficacy of the medium resolution 'mono' Imaging and stereoscopic imaging signal enhancement techniques employed by the Mk.5 and modified Mk.3 telescopes. The culmination of the evolution of the Durham telescopes is the Mk.6, described in Chapter 7. Its sensitivity is enhanced by high resolution imaging and the capacity to make observations at energies deficient in background events. Chapter 8 summarises the contemporary status of atmospheric Cerenkov astronomy.
8
Hild, Kerstin [Verfasser]. "Femtosecond laser-based investigations of magnetic circular dichroism in near-threshold photoemission / Kerstin Hild." Mainz : Universitätsbibliothek der Johannes Gutenberg-Universität Mainz, 2011. http://d-nb.info/1221804103/34.
Full text
9
Al, Tobi Amjad Mohamed. "Anomaly-based network intrusion detection enhancement by prediction threshold adaptation of binary classification models." Thesis, University of St Andrews, 2018. http://hdl.handle.net/10023/17050.
Full textAbstract:
Network traffic exhibits a high level of variability over short periods of time. This variability impacts negatively on the performance (accuracy) of anomaly-based network Intrusion Detection Systems (IDS) that are built using predictive models in a batch-learning setup. This thesis investigates how adapting the discriminating threshold of model predictions, specifically to the evaluated traffic, improves the detection rates of these Intrusion Detection models. Specifically, this thesis studied the adaptability features of three well known Machine Learning algorithms: C5.0, Random Forest, and Support Vector Machine. The ability of these algorithms to adapt their prediction thresholds was assessed and analysed under different scenarios that simulated real world settings using the prospective sampling approach. A new dataset (STA2018) was generated for this thesis and used for the analysis. This thesis has demonstrated empirically the importance of threshold adaptation in improving the accuracy of detection models when training and evaluation (test) traffic have different statistical properties. Further investigation was undertaken to analyse the effects of feature selection and data balancing processes on a model's accuracy when evaluation traffic with different significant features were used. The effects of threshold adaptation on reducing the accuracy degradation of these models was statistically analysed. The results showed that, of the three compared algorithms, Random Forest was the most adaptable and had the highest detection rates. This thesis then extended the analysis to apply threshold adaptation on sampled traffic subsets, by using different sample sizes, sampling strategies and label error rates. This investigation showed the robustness of the Random Forest algorithm in identifying the best threshold. The Random Forest algorithm only needed a sample that was 0.05% of the original evaluation traffic to identify a discriminating threshold with an overall accuracy rate of nearly 90% of the optimal threshold.
10
Wang, Shiyuan. "Fatigue crack threshold and growth behaviour in a near fully-lamellar gamma based titanium aluminides." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6347/.
Full textAbstract:
Fatigue crack threshold (\(D\)K\(_{th}\)) and fatigue crack growth of a near fully-lamellar \(y\)-TiAl alloy (Ti-4522XD alloy) have been investigated in air at room temperature, 400, 650, 700 and 750 oC and at three R ratios (0.1, 0.5 and 0.8). Studies were carried out on both corner-cracked specimens and smooth specimens. A combination of a \(D\)K- increasing loading method and growing a crack from notch were applied throughout the tests. As a consequence of consistent material microstructure, use of standardized testing procedure and a sufficient number of tests, some trends in fatigue threshold and crack growth have been established, including: trends include: lack of dependence of (\(D\)K\(_{th}\)) values on test temperature; average (\(D\)K\(_{th}\)) values decrease with increasing R ratio; a strong dependence of crack growth rate on K\(_{max}\) values at RT; a reduced dependence of crack growth rate on K\(_{max}\) values and increased plasticity at elevated temperatures; crack blunting causes a reduction of fatigue crack growth rate at R=0.8 and at elevated temperatures; and little effect of test temperature on ‘fracture toughness’ values. Above all, the origins of naturally initiated cracks under cyclic loading are often found to be centered on up to four colonies which have failed by interlamellar fracture.
11
Ravi, Ajaay. "Run-Time Active Leakage Control Mechanism based on a Light Threshold Voltage Hopping Technique (LITHE)." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1302550444.
Full text
12
Homer, Daniel C. "Population Fit Threshold: Fully Automated Signal Map generation for Baseline Correction in NMR-based Metabolomics." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1271689072.
Full text
13
Martindale, Linda. "Threshold concepts in research and evidence-based practice : investigating troublesome learning for undergraduate nursing students." Thesis, Durham University, 2015. http://etheses.dur.ac.uk/10998/.
Full textAbstract:
Across healthcare, evidence-based practice (EBP) has been recognised as a core component of providing safe and effective patient care and, consequently, research and EBP are important components of the undergraduate nursing curriculum. Despite the attention given to research and EBP in nursing education literature, the evidence base for effective learning and teaching strategies is weak. There is also evidence that undergraduate nursing students find aspects of these topics difficult and that negative attitudes may be a barrier to learning. However, little is known about the detail and processes of learning in this area. This narrative research study investigated the difficulties that nursing students encountered in learning about research and EBP and explored changes and transformations in their understanding. Using threshold concepts as a theoretical framework, the study aimed to identify thresholds associated with research and EBP, in the context of undergraduate nursing education. Seventeen third year students, from a large school of nursing, took part in at least one unstructured narrative interview and 13 of these gave two interviews, at the beginning and end of a research and EBP module. The interviews explored learning during the module, as well as students’ experiences in the first two years of their study. This included learning in practice and university settings. The findings show that the learning environments were characterised by variability and complexity. Students encountered different sources of trouble in their learning and they demonstrated varying degrees of change and transformation, which also linked to their developing nursing identity. From the narratives, a set of academic thresholds concepts emerged that underpins acquisition of a professional threshold of evidence-based thinking and practising. These findings have implications for undergraduate nursing curricula and suggest that there are changes required in education and practice settings, for EBP to be embedded in nursing practice and identity.
14
Giang, Truong Minh Triet, and trietgiang@yahoo com. "Efficient Admission Control Schemes in Cellular IP Networks." RMIT University. Electrical and Computer Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20060829.113000.
Full textAbstract:
The thesis reviews current admission control schemes in cellular IP networks. It proposes an improved version of Threshold Access Sharing and a new scheme: weight-based scheme. Finally, an admission control scheme for hierarchical cellular network is introduced.
15
Johanson, Jamin K. "An Evaluation of State-and-Transition Model Development fo Ecological Sites in Northern Utah." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/920.
Full textAbstract:
Ecological sites and state-transition models (STMs) have become the preferred means of summarizing plant community dynamics on distinctive types of rangeland. Ecological sites classify rangeland types based on soil-geomorphic and climatic conditions capable of producing a known plant community, while a STM depicts the vegetation dynamics of an ecological site. STMs are usually based on expert opinion rather than site-specific data; however, if they are to gain credibility, STMs must accurately describe the processes that drive plant community dynamics. This study examined three ways of developing process-based STMs using three levels of commonly collected field data. We began by taking field inventories of three ecological sites already mapped in northwestern Utah: Loamy Bottom, Mountain Gravelly Loam, and Upland Loam. The Loamy Bottom site was ideal for developing a data-rich, process-based STM because 1) the site concepts were well-defined, 2) the site was easy to recognize, 3) potential states and transitions had already been hypothesized, and 4) the site was easily accessible. The Loamy Bottom study was designed to link plant community structural indicators to measurable indicators of ecological process. Principal components analysis and cluster analysis were used to classify 14 study plots into four distinct states. Simple linear regression showed relationships between perennial grass cover, perennial canopy gaps, and soil organic carbon. Analysis of variance (ANOVA) linked four general vegetation classes to soil stability measurements. The resulting STM describes the structure and function of four alternative states. The other two STMs, developed for the Mountain Gravelly Loam and Upland Loam ecological sites, used less-intensive data collection methods. Rangeland health assessments, used for the Upland Loam STM, are useful for refining initial ecological site and STM concepts, documenting states, hypothesizing transitions, and locating study locations for future research. Quantitative production and cover estimates, used for the Mountain Gravelly Loam STM, are useful for describing the structure of states, but structural indicators must be coupled with process measurements, as with the Loamy Bottom STM to understand the drivers of state change. A coordinated data collection effort is needed to produce STMs that accurately depict the plant community dynamics of ecological sites.
16
Huber, Florian. "Structural breaks in Taylor rule based exchange rate models - Evidence from threshold time varying parameter models." WU Vienna University of Economics and Business, 2017. http://epub.wu.ac.at/5461/1/wp244.pdf.
Full textAbstract:
In this note we develop a Taylor rule based empirical exchange rate model for eleven major currencies that endogenously determines the number of structural breaks in the coefficients. Using a constant parameter specification and a standard time-varying parametermodel as competitors reveals that our flexible modeling framework yields more precise density forecasts for all major currencies under scrutiny over the last 24 years.Series: Department of Economics Working Paper Series
17
Lin, Wei-Ting, and 林煒珽. "Steganography Based on Threshold Secret Sharing." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/sdghuw.
Full textAbstract:
碩士國立臺灣海洋大學
資訊工程學系
105
Secret sharing is a very important part of modern cryptography. Secret image sharing technology is the expension of traditional secret sharing. When using this technology to share images, this technology can ensure the integrity and security of the secret image. This thesis discussed the main of steganography based on threshold secret sharing, so QR code applied to information hiding with the properties of storage data and error correction capability. The dealer generated shadow images by using secret image sharing scheme. Then user recorded the pixel values of shadow images, and transform into QR code by a program. To ensure QR code is maliciously destroyed that can decode and obtain the pixel value of the shadow images, thus restoring the secret image of the dealer. In this thesis, secret image used n shadow images which is generated from (t, n) threshold secret image sharing scheme. If the dealer wants to restore the secret image, he needs at least t shadow images. Besides, QR code as a watermark embedded in the original image as well as cropping, brightness, and compression attack watermarked image in the part of watermark test. After the QR code is extracted, the participanting party determine the QR code whether it can be transformed into shadow images. Finally, we show the secret image sharing and restoring scheme in this thesis is feasible by restoring the secret image from shadow images, and ensure the integrity and security of secret image.
18
Chun-Chung, Yu, and 游俊忠. "Evolutionary Threshold-based Business Rating System." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/81418865721017798361.
Full textAbstract:
碩士國立高雄應用科技大學
資訊管理研究所碩士班
96
In recent years, the serious financial issues occurred frequently. For example: Asian Financial Crisis, Subprime Mortgage. These crises have related to bank inadequacy management. Loan business is a major source of bank profit. Most of all loans belonging to enterprise loans. Therefore, the management of corporate default risk, it is much more important. Many country are active in Basel II as the main guiding principles for credit risk management related reforms. Basel II suggest banks to adopt the IRB( Internal Rating Based Approach). IRB allow banks to own strategy based on demand. It can build more autonomy and flexibility credit risk rating system. Statistics model and variable selection method are important elements of default forecast model. Logistic regression is a simple and easy-to-use regression model. It only applies to solve the problem of divided into two categories forecast. Although the cumulative logistic regression model can be divided into many categories. But the cumulative logistic S-curve of the cumulative probability that hard to distinguish between the thresholds. In this study, we use of multiple combinatorial logistic regression to improve and combine genetic algorithm to develop Evolutionary Threshold-based Business Rating System. Finally, we verified multiple combinatorial logistic regression model and TCRI model by Basel II proposing method. The experimental results found that in addition to the stability of model no better than TCRI. Use samples that close to default time to training MCLR rules will be more effective forecasting.
19
Chen, Huei-Ju, and 陳蕙茹. "Threshold Signature Schemes Based on Quadratic Residue." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/52885485616990182011.
Full textAbstract:
碩士國立臺灣大學
電機工程學研究所
90
Due to the fast progress of computers and communication networks, more and more electronic services are provided. Many of them require digital signatures such as voting and document issuing. By distributing power of generating signatures among a group of people, threshold signatures not only secure the group private key but also increase the availability of the signing service. Existing threshold signatures are based on either discrete logarithm or RSA. However, most of them require many exponential operations and some even have very cumbersome mathematical structures. In this thesis, we propose a user and signer efficient threshold signature scheme based on QR to achieve security as well as efficiency. Two modifications are also presented, the first one to enhance availability of signing service and the second one to add anonymity and traceability. These proposed schemes are shown to be correct, secure, robust, as well as computationally efficient. Also adversaries would not be able to forge signatures on a message. The efficiency of proposed schemes would meet the need for more and more sophisticated and advanced electronic and Internet services.
20
Huang, Po-Kai, and 黃柏凱. "speech enhancement based on audible masking threshold." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/79153188367709186735.
Full text
21
Huang, Shao-nung, and 黃劭農. "Identity-based multi-proxy threshold signature scheme." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/68572252859043360980.
Full textAbstract:
碩士逢甲大學
資訊工程所
95
We present three identity-based multi-proxy threshold signature schemes. First one is easier to manage. the second one is anonymity, the third one is anomymity and traceable. The main features of our proposed work are: (a)ID-based scheme reduces certificate management, (b) riginal signers and proxy signers are both allowed to be a group (c) only t or more proxy signers of the group can cooperatively issue a proxy signature on behalf of the original signer group, (d) the first and the third proposed schemes, we allow anyone join the original group without reset the system, (e) we support anonymity ability for the second and the third proposed schemes, (f ) in traceable scheme, if it’s necessary we can trace the co-signers of a certain signature. Furthermore, our proxy signature scheme is shown to be secure against forgery attacks.
22
Huang, Chung-Yuan, and 黃宗元. "Threshold Proxy Signature based on GQ scheme." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/09427588242274926553.
Full textAbstract:
碩士國立交通大學
資訊科學系
91
A (t,l) threshold proxy signature is a signature scheme that is designed to delegate the original signer signing capability to a designated group of l proxy signers. Only any t or more proxy signers of the designated group can generate the proxy signature behalf of the original signer. In this thesis, we propose the first (t,l) threshold proxy signature scheme based on GQ signature. The proposed scheme satisfies all requirements of a proxy signature and a threshold signature under adaptive adversary.
23
Huang, Xiao-Wei, and 黃曉偉. "An RSA-based (t, l) Threshold Proxy Signature." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/89591276325242220711.
Full textAbstract:
碩士國立臺灣海洋大學
資訊工程學系
95
In this thesis we propose and analyze a new RSA-based proxy signature scheme and its corresponding (t, ) threshold scheme. Unlike numerous previous research works, the threshold proxy scheme does not require any trusted combiner and is thus a truly practical approach. The security of both schemes is based on the RSA assumption. Both schemes are existentially unforgeable against no message attack in the random oracle model and especially the threshold proxy scheme inherits the merit of its predecessor - Shoup’s RSA threshold scheme - and thus is secure under a multi-party computation setup with active adversaries.
24
Hung, Yuan-Ying, and 洪沅瑩. "Analysis of Charge Pump Based Threshold-Compensated Rectifiers." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/kvxp4z.
Full textAbstract:
碩士國立勤益科技大學
電子工程系
105
Wireless sensor network (WSN) require sensor nodes which must be small with simple structure and low cost. It also needs long-distance communication technique to obtain a variety of information and to minimize the number of base stations. How to supply a continuous power to sensor nodes is a key issue of WSN design. Therefore, energy harvesting techniques become increasingly important in solving WSN power supply issue. The main building block in a radio frequency (RF) energy harvesting system is an RF to direct current (DC) rectifier. Based on both TSMC 0.18μm and 90 nm CMOS processes, the different threshold voltage (VTH) MOS transistors will be used in design RF to DC rectifier to study the design tradeoff between VTH and leakage current. In addition, voltage attenuation and dead zone problems existed in the traditional charge pump will be discussed. The experiment environment is set to be input frequency at 900MHz, RF input voltage peak 0.4V, and the load current 15uA or load 1 M Ω, to explore the conversion efficiency (η). Experimental results of FCR (Feedback Compensation Rectifiers, FCR) rectifier show that the output voltage is boost to 2.13V and the efficiency is 48.59% by using Normal_2 TSMC 0.18um process technology. If the 90nm Normal_2 used to design RF to DC rectifier, the post-sim output voltage is 2.01V and the efficiency is 15.06%. Experimental results of CR5S (Cross-Coupled Rectifiers 5 Stage, CR5S) rectifier show that the output voltage is boost to 1.49V and the efficiency is 25.63% by using Normal_2 TSMC 0.18um process technology. If the 90nm Normal_2 used to design RF to DC rectifier, the post-sim output voltage is 1.73V and the efficiency is 0.82%.
25
Tran, Ngoc Dang Khoa, and 陳玉登科. "Design of Threshold Accelerometer Based on Multistable Mechanism." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/m5hp6b.
Full textAbstract:
博士國立中興大學
精密工程學系所
106
A compliant tristable mechanism (TM) has been applied to develop a threshold accelerometer. The accelerometer is capable of sensing two distinct inertial signals when acceleration thresholds are exceeded along one axis. This function allows the flexibility to detect two consecutive events with the expected threshold values of the stimuli or two level quasi-static acceleration thresholds. The TM is a series connection of two bistable mechanisms (BMs). An analytical model based on a chained beam constraint model (CBCM) is developed for design and characterization of the TM. Feasibility of the device is demonstrated by experiments. The developed analytical model for the TM is verified by finite element analyses and experiments. Detection accuracy and fault tolerance can be enhanced by the thresholds created by snap through behavior of the TM.
26
Cheng, Chung-Chuan, and 鄭中川. "Automated Lung Segmentation Based on Grey-level Threshold." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/4f5feu.
Full textAbstract:
碩士朝陽科技大學
資訊管理系碩士班
94
Lung is one of the most important organs in the body. Medical Image analysis can be used to aid the diagnosis for the clinicians, to trace the progression of diseases. By applying the object segmentation technique in medical images, the contours of organs can be detected and used to analyze the tissue characteristics. Subsequently, these can be provided to doctors and researchers to aid their works. X-ray is the most widely used imaging modality for diagnosing diseases occurred in the chest and other anatomical organs. It is cheap and commonly taken routinely. This study investigates PA View chest radiographs. Canny edge detector and active contour models (ACM) are widely used techniques for object segmentation in medical images. However, the main weakness of the ACM is that an initial contour must be given so that the contour can be attracted to a proper position. In addition, it is time-consuming. For application in lung segmentation, it is easy to be interfered by the rib cage. This study proposes a fast method for lung segmentation. Salient features of chest images are used to locate the lung field. After the Canny edge detector has been adopted to detect edges and to find the approximated contours of the III lung lobes. Finally, the contours of the lung lobe with great accuracy can be obtained.
27
"Testing of threshold logic latch based hybrid circuits." Master's thesis, 2013. http://hdl.handle.net/2286/R.I.20796.
Full textAbstract:
abstract: The advent of threshold logic simplifies the traditional Boolean logic to the single level multi-input function. Threshold logic latch (TLL), among implementations of threshold logic, is functionally equivalent to a multi-input function with an edge triggered flip-flop, which stands out to improve area and both dynamic and leakage power consumption, providing an appropriate design alternative. Accordingly, the TLL standard cell library is designed. Through technology mapping, hybrid circuit is generated by absorbing the logic cone backward from each flip-flip to get the smallest remaining feeder. With the scan test methodology adopted, design for testability (DFT) is proposed, including scan element design and scan chain insertion. Test synthesis flow is then introduced, according to the Cadence tool, RTL compiler. Test application is the process of applying vectors and the response analysis, which is mainly about the testbench design. A parameterized generic self-checking Verilog testbench is designed for static fault detection. Test development refers to the fault modeling, and test generation. Firstly, functional truth table test generation on TLL cells is proposed. Before the truth table test of the threshold function, the dependence of sequence of vectors applied, i.e., the dependence of current state on the previous state, should be eliminated. Transition test (dynamic pattern) on all weak inputs is proved to be able to test the reset function, which is supposed to erase the history in the reset phase before every evaluation phase. Remaining vectors in the truth table except the weak inputs are then applied statically (static pattern). Secondly, dynamic patterns for all weak inputs are proposed to detect structural transistor level faults analyzed in the TLL cell, with single fault assumption and stuck-at faults, stuck-on faults, and stuck-open faults under consideration. Containing those patterns, the functional test covers all testable structural faults inside the TLL. Thirdly, with the scope of the whole hybrid netlist, the procedure of test generation is proposed with three steps: scan chain test; test of feeders and other scan elements except TLLs; functional pattern test of TLL cells. Implementation of this procedure is discussed in the automatic test pattern generation (ATPG) chapter.Dissertation/Thesis
M.S. Electrical Engineering 2013
28
WANG, YEN-TING, and 王彥婷. "A HIGH PERFORMANCE THRESHOLD VOLTAGE BASED TEMPERATURE SENSOR." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/03935992866969689706.
Full textAbstract:
碩士大同大學
電機工程學系(所)
98
A smart temperature sensing system with digital output consists of a temperature sensor and a voltage reference in the front end and an analog-to-digital converter (ADC) in the back end. In this thesis, a threshold-voltage based temperature sensor has been presented, and a low temperature coefficient voltage reference is achieved by using a pn-junction proportional to absolute temperature (PTAT) current generator to compensate the threshold-voltage based temperature sensor. In addition, a 7-bit flash ADC has been designed to convert the output of the temperature sensor to a digital code. The simulation results obtained from HSPICE using a standard TSMC 0.18um CMOS models and 1.8V power supply are presented in this thesis. This sensor is almost insensitive to the supply and is very linear dependent to temperature. The simulation result shows that the voltage output of the sensor has the temperature error of ±0.07°C from -20°C～100°C, and temperature coefficient of it is -1.239 mV/°C. The low temperature coefficient voltage reference has the result of 1.51V, and the temperature coefficient is 1.058ppm/°C. The 7-bit flash bit has the INL of 0.32LSB, and DNL of 0.38LSB, which can meet the requirement of the temperature sensing system with 1°C resolution.
29
Wang, Zhi-Wei, and 王志暐. "Threshold-Based Admission Control for an MMS Server." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/83195093885446878932.
Full textAbstract:
碩士元智大學
資訊工程學系
92
Multimedia messaging service (MMS) promises a dramatic increase in messaging capabilities that will enrich user experience and a major new source of revenue for network operators as well as content and service providers. However, despite the advances in this area, the ability to exchange large amounts of information further fuels the demand for more resource-intensive applications and affects the bandwidth allocated for ensuing transactions. In addition, delays perceived by users can increase depending on the size and location of the multimedia content. In this paper, we propose a QoS control strategy, called Threshold-Based Admission Control (TBAC), for an MMS server supporting two types of MMs: high- and low-priority. Taking the forwarding and the expiration effects of queued MMs into account, this paper develops an analytical model to study the TBAC performance. On the basis of the analysis, the optimal threshold for the TBAC strategy is numerically determined so that the bandwidth is efficiently utilized and the QoS requirements for both classes of MMs are satisfied.
30
Liu, Yi-Cheng, and 劉毅成. "Image Sharing Based on Shamir's (k, n) Threshold Scheme." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/83465976504422940023.
Full textAbstract:
碩士國立清華大學
資訊系統與應用研究所
99
一般典型的秘密影像分享技術，是由一莊家將秘密影像切分成n張分享的子圖，並交由n位參與者保管，使得只要收集到其中任k張就能回復秘密影像，同時若少於k張則無法得知足夠的訊息去還原這張秘密影像。這個影像分享的觀念來自於1979年，由Blakley及Shamir所各別研究提出的(k, n)門檻方法。 在本篇論文中，我們提出一個方法來實作秘密影像分享，其中利用affine cipher的概念與林志青教授等所提出的架構，來得到重組後的影像與產生分享的子圖。在所提出的方法中，於分享的步驟前，我們選定(a, b)兩個數來當作鑰匙，並利用它們來對像素位置做洗牌，同時保有原來直方圖的分布。這個方法打亂了原來像素間的相關位置，避免使分享的子圖暴露出秘密影像的輪廓。我們提供了兩張影像與兩組重組鑰匙來做為實驗結果。
31
Wu, Cheng-Han, and 吳承翰. "(4,6)-Threshold Image Sharing Based on Chinese Remainder Theorem." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/f3uu5s.
Full textAbstract:
碩士國立清華大學
資訊工程學系所
106
For the reason that the rapid growth of information in the era of Big Data nowadays, information security plays an important role. To avoid secret information carried by single carrier, this thesis studied image sharing based on (k,n)-threshold scheme, which distributes a secret image to n shadow images preserved by n participants. Collect at least k of them, we can recover the secret image, but fewer than k of them could not. We proposed a method for the extension of Chuang’s scheme [Chua2016] based on Chinese Remainder Theorem in this thesis. Compared to other image sharing methods, our method is much simpler and efficient. Although the recovered image in our method has the difference of the least significant bit with the secret image, the experimental result shows that human beings can hardly distinguish two pictures with PSNR value over 50db. Moreover, we can additionally process the least significant bit of each pixel during the sharing and recovering parts if we want to recover the image completely.
32
Syu, Jhih-Hao, and 許智豪. "Reliable Heterogeneous Mobile Cloud Storage Based on Threshold Technology." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/96044018892634842204.
Full textAbstract:
碩士樹德科技大學
資訊工程系碩士班
101
Due to the popularity of cloud computing, a lot of cloud services have created. Therefore, the cloud storage service is one of the most characteristic services in recent years. Before the cloud storage service has not been prevalent, the data generally exist inside the hard disk. However, because the aging of cloud storage technology, many today''s service providers have been offering unique conception of cloud storage services. Its advantages such as: (1) On-line without hindrance: As long as accessing to the Internet, there are immediate features of on-line or off-line. (2) Simple operation: Neither having to learn difficult IT technology nor need to update or repair. (3) Suitable for the development of applications: Related service providers will release the development documents for development community. (4) Without purchasing any hardware and save cost. In summary, cloud storage services gradually are the general public''s favorite, also an increasing number of businesses use it to store data. Consequently, the user interfaces of the service providers are different, so that the files on cloud storage services emerged inconvenience and safety concerns. For example, there are confidentiality problems of files stored in the cloud storage service, as well as the availability problem due to service interruptions resulting file missing. Therefore, we hope to create a unified operating platform to enhance the confidentiality of cloud file storage services. And if a service interruption resulting in missing files, the system can recover files through several service providers systems. In this thesis, threshold secret sharing and WuKong heterogeneous cloud storage system are the thesis''s main frameworks. Threshold secret sharing depends on the user’s settings, scatter secret content into many a pieces and it doesn''t have any meaning. But if having not taken back definite framework can combine different cloud storage service resource. And users can set operating pattern independently, integrating with different operating platform, let the users be easy stocking data. Therefore, this paper is aimed at Wukong''s way and present misgiving of cloud storage service suggest some hiatus, such as keep the file in the confidentiality of cloud storage service, service abort leads to file lose. For solving this kind of problem, utilize the method in this paper, for instance, threshold secret sharing to solve users’ mistrust and data safety with cloud storage service, and research HDFS now to restoration lose or destroy data. The framework of this research is integration of different cloud storage service''s API, scatter threshold''s principle to solve the file''s adaptability, and cryptographic symmetric encryption to increase confidentiality. Finally, integrate various platform, increase users convenience and look for more efficient encryption method to increase file confidentiality and adaptability. The implementation of this system is mainly in the mobile device environment, the hardware specifications includes CPU 1.6GHz quad-core processor, 2GB RAM and 32GB ROM, the system environment for the Android 3.0 Honeycomb or more. Development environment includes Eclipse Developer, Android SDK, Java JDK 1.6, DropBox Android SDK 1.5.4 and SQLite database system.
33
Ren, Deng Yi, and 任登義. "ATM AAL receiver design supporting threshold based buffering mechanism." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/35021372177170968123.
Full textAbstract:
碩士國立臺灣大學
資訊工程學研究所
84
A broad-band terminal adaptor (BTA) is needed in the internetworking unit between LANs and ATM network to provide the necessary conversion of data packets. The ATM adaptation layer (AAL) design is the kernel component in BTA. In this thesis, we examine the AAL5 BTA implementation problems and discuss some of their solutions. Design issues of AAL5 consists of the transmitting end and the receiving end. In the transmitting end, AAL5 deals mainly with data segmentation and generates CRC field. At the receiving end, the AAL5 entry receives ATM cells, reassembly them into a upper layer PDU, detects error and handles cell loss. In this thesis we focus design issues at the receiving end. Since an AAL5 may support multiple virtual channels at the same time, at AAL5 entry receiving end needs to be equipped with sufficient reassembly buffers to temporarily store many partially-reassembled messages. Meanwhile, if the host interface is busy and network is heavy loaded, how the BTA handle heavy traffic becomes an essential issue. For example, if one can reduce the events of discarding cells due to buffer overflow the packet level throughput can be improved. Here we propose a useful buffer management mechanism, which is named Threshold-Based Buffering Mechanism, to reduce performance degradation level. This mechanism sets a threshold on reassembly buffer. In congestion, once reassembly buffer space excesses threshold, the receiving end BTA will choose the longest packet in reassembly buffer and then deliver part of it to the upper layer even it is still incomplete.
34
Tang, Chi-Feng, and 唐啟峰. "A Threshold-based Matching Algorithm for Photonic Clos Network Switches." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/32266835842900584556.
Full textAbstract:
碩士國立中興大學
資訊科學研究所
94
This thesis is concerned with a cell matching algorithm for the three-stage Clos network. The three-stage Clos network not only provides more switch capacity but also decreases the numbers of switch elements in the network. Matching algorithms are used to solve the scheduling problem on the Clos network. In this thesis, we propose a new matching algorithm, with features of the cut-through, variable threshold mechanism and preemption mechanism. Our study on performance evaluation focuses on the bursty traffic model. We present the simulation results by t-MAC, and show the improvement of transmission efficiency.
35
Chen, LungHsi, and 陳隆熙. "A Reliable Solver of TSP─Based on Threshold Accepting Algorithm." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/16429388038282845419.
Full textAbstract:
碩士大葉大學
工業工程研究所
90
Threshold Accepting（TA）method is a meta-heuristic algorithm to solve the optimization problem. Like the Simulated Annealing（SA）method, the result of TA varies from one run to another. Here we propose to find a reliable TSP solver such that the optimal solution is guaranteed within a specified number of function evaluations. The method is called “Double Threshold Accepting Algorithm”, or called Double TA for short. In this algorithm, the threshold value is decomposed into two parts : normalized threshold value and cap. The threshold value is equal to normalized threshold value multiplied by cap. First, we plan to find that with a proper selection of threshold values in TA, the empirical result shows it always converges to the optimal solution in the regular-grid TSPs. The experiment will be performed on 18 cases ranging from 16 through 441 points（cities）and each case is executed 100 times. We desire that they all converge to the optimal solution within the specified limit of number of function evaluations. The pattern of threshold is in the shape of natural cubic spline and can be constructed by several control points. The scale is termed cap and can be obtained from the cap function of positive changes of the cost function in the step of move from a sub-optimal tour to a global optimal tour. The TA is performed twice in our implementation where the name “Double Threshold Accepting” is derived. The second run of the TA makes sure the optimal value is obtained in case it slips away from the optimal in the first run. Furthermore, we plan to apply it to other practical problems listed in the literature especially the Grotschel’s pcb442 problem. This problem is notorious because it has many degenerate points nearby the global optimal.
36
Chang, Ching-Lueh, and 張經略. "Analysis of Threshold-Based Processes of Cascading Activation in Graphs." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/00673767390340864352.
Full textAbstract:
博士臺灣大學
資訊工程學研究所
98
Let $G(V,E)$ be a simple directed or undirected graph and $phi(v)geq 1$ for each $vin V$. The following process and its variants have been studied extensively in the literature. Initially, only a set of vertices, called the seeds, are active. Thereafter, an inactive vertex $v$ is activated when at least $phi(v)$ of its in-neighbors are active. The process ends when no additional vertices can be activated. We derive bounds on the minimum number of seeds needed to activate at least a $deltain [0,1]$ fraction of the vertices at the end, for the following cases: egin{itemize} item $G$ is an Erd{H{o}}s-R{''e}nyi random graph. An inactive vertex is activated when at least a $ hoin [0,1]$ fraction of its neighbors are active. item $G$ is a connected undirected graph. An inactive vertex is activated when more than half of its neighbors are active. item $G$ is a directed graph with positive indegrees. An inactive vertex is activated when at least half of its in-neighbors are active. item $G$ is a directed graph with positive indegrees. An inactive vertex is activated when more than half of its in-neighbors are active. item $G$ is a directed graph, $phi(v)geq 1$ for all $vin V$ and $delta=1$. end{itemize} We also investigate the computational hardness of finding a minimum set of seeds activating all vertices at the end.
37
Chen, Yu-Gou, and 陳裕國. "Estimating the Green Threshold of Enterprises Based on Utility Matrix." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/50959339610915103911.
Full textAbstract:
碩士康寧大學
運籌與科技管理研究所
99
With the current global warming crisis, the obvious greenhouse gas effect has had an impact on the sustainable development of many, if not all countries that it has been one of the main concerns of the government and the citizenry. Government agencies and non-profit organizations actively discuss the necessary measures for environmental protection and promoting afforestation, especially the setting in place of an evaluation system which is expected to help determine the measures necessary to recover the original appearance and function of natural ecology. Global environmental greening campaigns not only appeal to the enterprises to develop various business opportunities from the use of green energy but also to actively create a green enterprise image, advocate environmental and social responsibility and enhance operations by remaining competitive in this aspect. It will be the future trend for enterprises to invest in environmental protection and to incorporate the setting up of a green management into their operations. The research mainly discusses the level of participation towards environmental protection and afforestation by case enterprises in Taiwan in the course of their operations, and applies the multiple criteria decision making as the basis for the research methods. First and foremost, reports of Greenbiz Company were taken to assess the index and a set of assessment index system for the environmental protection and afforestation programs of enterprises was established. The companies’ afforestation and environmental protection programs were sorted and classified, and the elements used for the assessment methods were analyzed. There are 6 dimensions and 21 standard elements. The 6 dimensions include green economy and industrial structure, green innovation, social responsibility, environmental impact, employees and working environment and the use of resources. Then according to the experts’ questionnaire survey, weighting of dimensions and criteria will be calculated using the method of analytic hierarchy process. In addition, grading the threshold value of every element will be calculated using the questionnaire given to enterprises. Finally, the VIKOR ranking method which can produce compromising solutions will be applied to rank the case enterprises in Taiwan and discuss the level of afforestation participation in the course of their operations and rank them in terms of quality. Based on the results of the research, strengthening the dissemination process of green information and presenting competitive advantages of green companies are indicated as some of the strategies that can be done. Screening qualified case enterprises to improve the competitiveness and enterprise image is also considered so as to help them obtain maximum profits and margins. The highest goal is to improve operational efficiency while taking into account environmental protection measures and therefore create an enterprise with a sustainable operational environment.
38
Chang, Juei-Feng, and 張瑞芳. "Image Threshold selection based on PSO and 2D-Otsu Algorithm." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/90250525774143478346.
Full textAbstract:
碩士國立中央大學
通訊工程學系在職專班
101
Threshold selecting is a significant technique for image segmentation, which is applied broadly in many fields such as character recognition, analysis of biologic images etc. The method mainly includes P-tile method , the maximum entropy method , Otsu and so on. It is essentially a pixels classification problem. Its basic objective is to classify the pixels of a given image into two classes: one is those pertaining to an object and another is those pertaining to the background. While one includes pixels with gray values that are below or equal to a certain threshold, the other includes those with gray values above the threshold. As an extension of Otsu algorithm, two-dimensional Otsu algorithm (2D-Otsu) can give good result for those objects whose histogram does not have two peaks which represent objects and background, however, it costs complex computation. Particle swarm optimization (PSO) is a swarm intelligence optimization algorithm as a set few parameters, better global search capability, search results more stable and widely used. So we combined successfully these two algorithms to get ideal segmentation result with less computation cost.
39
Chung, Chun-Hua, and 鐘俊驊. "ILP-Based Multi-Threshold Voltage Assignment for Leakage Power Reduction." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/85654015920881135264.
Full textAbstract:
碩士中原大學
資訊工程研究所
97
Along with the shrink of Integrated Circuit (IC) process technology, the consumption of dynamic power reduces due to reduction of the supply voltage. However, the consumption of static power occupies a greater proportion of entire power consumption. The consumption of leakage power occupies about half of entire power consumption in 90nm process technology. Therefore, how to reduce the consumption of leakage power has become an important issue for the deep-submicron chip design in the future. This research paper proposes a method to reduce leakage power with the application of integer linear programming (ILP) on the swapping of multi-threshold voltage. The objective of this paper is to retain the performance of original circuit design while effectively minimizing the consumption of leakage power in various timing constraionts. First, we perform static timing analyze, as well as formulate the corresponding consumption of circuit power and timing model of integer linear programming. We then resolve the integer linear programming problem and acquire the optimal solution for the model of integer linear programming by using the commercial linear programming software (LINGO v11). This paper utilizes ISCAS’85 benchmark for the testing circuit; the benchmark circuit power consumption and timing model are realized with TSMC 90nm standard library. Comparing to the original design, the experimental results indicate that the dual-threshold and multi-threshold voltage approach can provide up to an average of 66.11% and 69.52% of leakage power reduction, respectively. In addition, the average runtime of our integer linear programming model in LINGO v11 for all circuits is less than three minutes.
40
Lin, Shu-Ying, and 林書瑩. "Stock returns and trading volume based on double-threshold models." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/21239669295383854335.
Full textAbstract:
碩士逢甲大學
統計與精算所
92
This paper examines the hypothesis that both returns and volatility respond asymmetrically to past volume and returns. The approach we adopt is based on a double threshold GARCH model. The main feature of this model is to allow the threshold nonlinearity in mean and volatility to be determined by lagged changes in trading volume and returns. The error terms are assumed to be fat-tailed distribution to capture the usual conditional leptokurtosis in financial return data. Estimation is performed using Markov chain Monte Carlo methods. The proposed methodology is illustrated using both simulated and international market index data. By employing our double-threshold GARCH model to investigate five major stock market return series, we find strong evidence to support the existence of return spillover effect and asymmetric relationships between returns and changes in trading volume. We also use the posterior odds ratio to determine which threshold model is the best among the standard GARCH and eight possible threshold GARCH models.
41
Lin, Ying-Hsiu, and 林映秀. "Triple Visual Secrets Sharing Scheme Based on (2,) Threshold Scheme." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/19918992101736917368.
Full textAbstract:
碩士嶺東科技大學
資訊科技應用研究所
97
Visual cryptography, the theme of this research, was first proposed by Naor and Shamir in 1994; Its greatest advantage is in decryption, which requires only superimposing the share images, no complicated computation or cryptology is required. Most traditional visual cryptology technologies are based on one secret image between two share images and the halftoning scheme to handle the gray-scale images. This research proposes a triple visual secrets sharing scheme with two share images-a three blacks and one white pixels Share A and a two blacks and two whites pixels Share B. By rotating clockwise and counterclockwise each 2*2 black of the Share A, it allows the two share images to hold three kinds of confidential messages. The construction, which based on (2,2) threshold scheme, handles Share A and Share B; also utilizes bit-level decomposition and superimposition techniques to replace the traditional halftoning scheme. This scheme, which is not affected by the different color tones, can be applied to black-white and grey-scale visual cryptography, and the color images as well. Moreover, the triple visual secrets sharing schemes in this study is an easy information hiding procedure and generates uniformly distributed share images. Keywords: Visual Cryptography, Share Image, Secret Image, Grey –Scale Image, Bit-Level, Color Image
42
Wang, Po-Hsueh, and 王柏學. "Downlink Scheduling Algorithm Based on Delay Threshold in LTE Systems." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/89hnnz.
Full textAbstract:
碩士國立中興大學
資訊科學與工程學系
103
Modified Largest Weighted Delay First (M-LWDF), Exponential Proportional Fair (EXP/PF), and Channel Dependent Earliest Due Date (CD-EDD) are commonly frequent referenced algorithms for downlink scheduling the requests of real time multimedia applications in LTE downlink systems. They take into account of both channel quality and packet delay in the decision of packet dispatching. However, when a packet gets close to its delay budget, it may be eventually dropped without raising its delivery priority quickly with M-LWDF, while the packet with good channel condition but short waiting time may not be scheduled due to its packets selection emphasizing on the earliest time to expire with CD-EDD, as well as with EXP/PF. By considering both the channel condition and packet waiting time, we propose a delay threshold scheduling (DTS) algorithm in this paper. We adopt delay thresholds to differentiate packets and apply different proportional weights between channel condition and waiting time to prioritize real time services. Simulation results show that, by adopting DTS, higher throughput for video traffic, lower packet delay and less packet loss ratio for real time services than M-LWDF, EXP/PF, and CD-EDD can be achieved.
43
Husaini and 胡桑尼. "A Threshold-based Cloud Resource Allocation Framework with QoS Considerations." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/p322cu.
Full textAbstract:
碩士國立交通大學
電機資訊國際學程
103
Resource allocation, which is the process of assigning the amount of resources needed by cloud applications, is very crucial concern in the service provision. If the allocation of resources is not managed precisely, the cloud services may starve during the peak load time or waste the resources during the off-peak time. Auto scaling mechanism is one approach used in IaaS in which service providers can maintain the resources and reduce waste resources by automatically increase or decrease them when needed. Some of the cloud services support auto-scaling functionality. However, it is still difficult to predict the client side experience which later will cause in decreasing performance because of lacking computing instances. In this paper, we focus on allocating resources at the application level rather than mapping the physical resources to virtual resources for the efficient resource utilization. We present a novel cloud resource management framework which supports dynamic auto-scaling. The proposed system will monitor the end-user’s response time directly from client-side. We defined several thresholds with Quality of Services (QoS) considerations which include response time and error rates sampling in order to optimize the decision of reallocating the virtual resources. The goal of this study was to dynamically allocate the virtual resource among the cloud applications based on their workload changes in order to improve resource utilization, prevent from resource starvation and reduce the user usage cost. The experimental results show the proposed framework can improve the efficiency of resource utilization.
44
Masunda, Kennedy Tohwechipi Fudu. "Threshold based multi-bit flipping decoding of binary LDPC codes." Thesis, 2017. https://hdl.handle.net/10539/24242.
Full textAbstract:
Submitted in fulfilment of the academic requirements for the Master of Science in Engineering in Electrical and Information Engineering degree in the School of Electrical and Information Engineering at the University of Witwatersrand, Johannesburg, South Africa.
August 2017There has been a surge in the demand of high speed reliable communication infrastructure in the last few decades. Advanced technology, namely the internet has transformed the way people live and how they interact with their environment. The Internet of Things (IoT) has been a very big phenomenon and continues to transform infrastructure in the home and work place. All these developments are underpinned by the availability of cost-effective, reliable and error free communication services. A perfect and reliable communication channel through which to transmit information does not exist. Telecommunication channels are often characterised by random noise and unpredictable disturbances that distort information or result in the loss of information. The need for reliable error-free communication has resulted in advanced research work in the field of Forward Error Correction (FEC). Low density parity check (LDPC) codes, discovered by Gallager in 1963 provide excellent error correction performance which is close to the vaunted Shannon limit when used with long block codes and decoded with the sum-product algorithm (SPA). However, long block code lengths increase the decoding complexity exponentially and this problem is exacerbated by the intrinsic complexity of the SPA and its approximate derivatives. This makes it impossible for the SPA to be implemented in any practical communication device. Bit flipping LDPC decoders, whose error correction performance pales in comparison to the SPA have been devised to counter the disadvantages of the SPA. Even though, the bit flipping algorithms do not perform as well as the SPA, their exceeding low complexity makes them attractive for practical implementation in high speed communication devices. Thus, a lot of research has gone into the design and development of improved bit flipping algorithms. This research work analyses and focusses on the design of improved multi-bit flipping algorithms which converge faster than single-bit flipping algorithms. The aim of the research is to devise methods with which to obtain thresholds that can be used to determine erroneous sections of a given codeword so that they can be corrected. Two algorithms that use multi-thresholds are developed during the course of this research. The first algorithm uses multiple adaptive thresholds while the second algorithm uses multiple near optimal SNR dependant fixed thresholds to identify erroneous bits in a codeword. Both algorithms use soft information modification to further improve the decoding performance. Simulations show that the use of multiple adaptive or near optimal SNR dependant fixed thresholds improves the bit error rate (BER) and frame error rate (FER) correcting performance and also decreases the average number of iterations (ANI) required for convergence. The proposed algorithms are also investigated in terms of quantisation for practical applications in communication devices. Simulations show that the bit length of the quantizer as well as the quantization strategy (uniform or non-uniform quantization) is very important as it affects the decoding performance of the algorithms significantly.
MT2018
45
Jing-YuHuang and 黃境昱. "A Reliable Near-threshold Voltage SRAM-based Physical Unclonable Function." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/3ff7jx.
Full text
46
Lai, Tien-Hsiang, and 賴天祥. "Threshold Biometrics-based Remote User Authentication Scheme Using Smart Cards." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/84566735069847588327.
Full textAbstract:
碩士中國文化大學
資訊管理研究所
97
Combing biometrics characteristics with usage of smart card for identification recognition has been widely discussed. Researches on the technology are addressed in the undeniable uniqueness for identification. Hwang-Li at year 2000 and Lee and et al. at year 2002 respectfully proposed identification frameworks based on the finger-print recognition. Their innovative algorithms allow finger-print identification. However, the proposed frameworks still have the problems of the security weakness, which are unable to avoid camouflage attacks. In this thesis, we have analyzed Hwang-Li and Lee’s algorithms and raised the issues of the security loophole. In advance, we propose an improved framework and the algorithms to amend the problem of the Hwang-Li and Lee’s system. To fix the shortcomings of Lee’s proposed framework, our proposed framework can ensure that only certified users are allowed to access the information in the system. In addition, our framework innovatively utilizes the secret sharing technology upon identity verification technology, which strengthens the security of the entire algorithm. To consider the users’ security while using the bio characteristics information, we have innovatively utilized secret sharing technology on the verification technology. Within this framework, not only the biometrics characteristics replace the passwords, but also the users are allowed to spread out a certain amount of information when needed and to modify their passwords directly. The proposed framework can protect the system from both the reply attacks and the offline-dictionary attacks. The effectiveness, security and privacy of our proposed framework are verified.
47
Li, Shih-hsun, and 李士勳. "Traceable identity-based threshold signature scheme with multiple signing policies." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/96958193977543784971.
Full textAbstract:
碩士逢甲大學
資訊工程所
95
We propose to work on identity-based cryptosystem that provides traceable threshold signature with multiple signing policies. There are four distinct features of the proposed systems: (a) identity-based public key, allowing uses to use name, email address and/or phone numbers as their public keys; (b) multiple signing policies, the threshold values can be chosen as different signing policies; (c) single private key for each user; and (e) all signers are traceable. Analysis will be given to show that our proposed cryptosystem is secure under various attacks.
48
Kan, Chia-Chao, and 甘家兆. "An Efficient Secure Broadcast Model for PHF-based Threshold Cryptosystems." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/02194404910583680880.
Full textAbstract:
碩士國立交通大學
資訊科學與工程研究所
94
The thesis targets for the particular requirement of secure broadcast on PHF (Perfect Hash Family)-based threshold cryptosystems on wireless networks, and we propose a method for doing such secure broadcast. There is a property on PHF-based threshold cryptosystems: The users in the system can be partitioned into groups by the shares they keep. In such perspective, the secure communication between groups and within groups will be an issue which is needed to be solved. If such issue has been solved, then we can play applications of "share renewal", etc. Moreover, consider the native property of communication on a wireless network. If we apply broadcast technique, then we can reduce the communication cost greatly. The paper in [1] gave a general secure broadcast scheme. It needs a TA (trust authority) to do the distributions of pre-key. However, in some wireless networks (Ex:Mobile Ad-hoc Network[2]), the existence of a TA is not practical at all. In the thesis, we propose a secure broadcast model on PHF-based threshold cryptosystems. It needs not a TA, and also, the communication cost while doing secure broadcast is less than [1].
49
Yang, Shun-Yuan, and 楊順元. "A secure e-mail system based on (2,2) threshold scheme." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/43930935730343885323.
Full textAbstract:
碩士國立雲林科技大學
電子與資訊工程研究所碩士班
90
Email has been the Internet’s killer application since 1970s. Early email systems were lack of security services to prevent sensitive information from disclosure. Though many variations of Email software such as PGP, PEM and S/MIME support secure email services, they cannot control the recipient’s behavior. For example, the recipient can copy, print, past and forward the important and sensitive emails intentionally or unintentionally. In this paper, we propose a new architecture of secure Email system based on (2,2) threshold scheme and cryptographic technology to not only provide confidentiality, integrity, authentication and nonrepudiation services during email transmission, but also control the recipient’s behavior according to the security rules set by the sender.
50
Huang, Pao-Wei, and 黃寶瑋. "An Uplink Scheduling Algorithm based on Adaptive Threshold in WiMAX Networks." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/47564556191485019011.
Full textAbstract:
碩士國立高雄應用科技大學
電機工程系
98
WiMAX network define Broadband Wireless Access(BWA).WiMAX provides high speed and wide range wireless network services. Although the WiMAX standard provided the main principles in designing a QoS architecture to support multimedia applications, the important issue is uplink scheduling, bandwidth allocation and admission control. In recent years, lots of researches in uplink schediing are focusing on system throughput and the issues how to uplink scheduling efficiently in WiMAX network becomes important. In this paper An Uplink Scheduling Algorithm based on Adaptive Threshold in WiMAX Networks (US-AT Algorithm) that focused system throughput and total revenue. This Algorithm used the rtPS queue size to determine the system to Non-Critical State or Critical State;In Non-Critical State, first set rtPS deficit counter to lower bound and change the nrtPS and BE deficit counter to get proportional or weighted. In the Critical State, first calculates the real-time application packet deadline and divide packets levels, finally use the ladder state to have adequate deficit counter..The US-AT algorithm could efficiently to improve the real-time requirements and provide more QoS guarantee in WiMAX network.