Dissertations / Theses on the topic 'Maximitid'

Due to the rapid development of telecommunication devices, operating speeds are getting faster and more power is being consumed by those devices. Therefore, there is a big concern on how to prolong the battery life in order to fit consumers’ needs. Power amplifiers (PA) at the front end of wireless equipment have drawn a big concern from engineers because of their large power consumption in the system. There is a lot research conducted on PA solutions for improving power-added efficiency (PAE) of amplifiers. PAE is a figure of merit representing how efficient the PA converts DC power to RF power. With PAE increased, the device is able to output the same amount of power with less DC power consumed. Non-linear Class-F and Class-F-1 PAs have drawn the most attention among all different classes of PAs from engineers because of their capability of outputting high power and providing good PAE. Class-F boosts up PAE by controlling the harmonic content at the output. Advanced Design System (ADS) from Agilent is used for design and simulation based on the ADS model of Cree’s CGH40010 high electron mobility transistor (HEMT). A high efficiency power amplifier is fabricated on RT/duroid 5870 high frequency laminate board. In this design, the harmonics at the input are controlled as well as the harmonics at the output. An input wave-shaping network is designed to shape the waveforms at the gate. In this case, the PAE is boosted 30% higher than the PA with only the output wave-shaping network. By terminating harmonics with proper impedances at the output, a square voltage waveform and a half-sine current waveform are obtained at the transistor drain terminal. The overlapping area between the voltage and current waveforms can be reduced as well as the active device power consumption. The final design operating at 1GHz produced a PAE of 89% with 38.35dBm output power in simulation and PAE of 78% with 38.7dBm output power as the result of the IEEE PA design contest. The thesis has shown the effectiveness of the Class-F PA to boost up PAE by preventing the 2nd and 3rd harmonic power from delivering to the load and shaping the waveforms at the transistor terminals. It also shows the benefit of using radial stubs in wave-shaping networks over open-circuit stubs.

Fuel efficiency is an ever present problem in today's modern world. The United States in particular is in need of a solution to lowering greenhouse gas emissions caused by transit and freight across its spread out cities. In fact in the United States the average commute time of an individual is 26 minutes, meaning that round trip people are driving about an hour every day, to and from work. But that gas consumption is pittiling compared to that of the freight industry. Heavy Duty Vehicles (HDVs) commonly known as semi trucks, account for three quarters of US freight emissions and 7.5% of total US greenhouse gas emissions [2]. But this can be cut down considerably with the implementation of platooning. Platooning is when multiple vehicles follow in close distance to reduce aerodynamic drag, causing significant fuel savings. In this paper, we will go over an algorithm to help vehicles join with already formed platoons on the road, increasing their fuel efficiency and therefore saving cost to the driver in addition to lessening the negative effect on the planet. This will be done using a modified A* algorithm. The base weight of zero will be the amount of gas the vehicle would consume taking the shortest path that google maps recommends, alone, with no platooning. Paths may end up with negative weights due to the fuel savings caused by joining existing platoons during the vehicles’ travel. The algorithm will have access to a map of the roadways and the GPS data of nearby platoons. It will then perform a cost-benefit analysis to determine if the fuel savings from joining a platoon will outweigh the cost of going outside of its original path in order to join the other vehicles.

Prenant son point de départ dans les travaux d’Ernst HOHL, de Susan H. BALLOU et de Blanche B. Boyer, et fondée sur une étude d'ensemble de la tradition manuscrite, cette Edition de la VITA MAXIMINORVM établit dans le détail le classement des différents groupes de manuscrits. L’archétype carolingien est au point de départ de deux lignées: la première a donné le jour à l'ancêtre des Vaticans Palatins latins 899 et 886; elle était connue dans ses grandes lignes, mises au point par HOHL; ayant refait nous-même le travail, nous avons fixe la position des témoins de ce rameau dont il ne faisait pas état, affine et redresse ses propositions. La seconde lignée a donné naissance à une copie, soumise très tôt à une révision attentive et qui a abouti à quatre branches; d'une de ces branches est sortie, après recension, une sous-famille qui se divise en deux sections de trois et cinq témoins. L’étude du texte de la VITA MAXIMINORVM a permis d'examiner dans le détail ces deux recensions, de voir quel genre d'améliorations - ou d'outrages - elles ont fait subir au texte
Starting from the research work done by Ernst HOHL, Susan H. Ballou and Blanche B. Boyer, and based on a full study of the manuscript tradition, this edition of the VITA MAXIMINORUM establishes a detailed classification of the various groups of manuscripts. The Carolingian archetype splits into two classes: the first one produced the common ancestor of the two Vatican, Pal. Lat. 899 and 886; it was known in its main outlines, worked out by HOHL; having undertaken this study ourselves, we have determined the position of the witnesses of the group he did not mention, refined or emended his propositions. The second line of descent generated a copy which was soon thoroughly revised and fell into four branches; after recension one of them led to a sub-group divided into two sections of three and five witnesses. The study of the text of the VITA MAXIMINORUM has allowed an investigation of these two recensions in order to track down the improvements or deteriorations - they produced

Carbon dioxide emissions to the atmosphere today cause problems around the world. In Sweden, the steel production contributes significantly to carbon dioxide emissions. The steel industry challenge is to improve the metallurgical processes to decrease the carbon dioxide emissions. One way to reduce the emissions is to use renewable carbon sources. The blast furnace process is a counter current reduction process for ironmaking. Raw materials such as iron ore agglomerates, coke and slag formers are charged at the top of the furnace while oxygen-rich blast air and powdered coal are injected in the bottom. The gases produced by combustion rise through the burden on the top of the furnace. The combustion of carbon produces carbon monoxide which is the reducing gas used for the reduction of iron oxides to pig iron. The process is the highest producer of CO2 emissions in Sweden; biomass can partially replace fossil carbon in coal blends for cokemaking, coal powder for coal injection and coke in self-reducing briquettes.  The purpose of this project was to maximize the addition of biomass in coal blends for cokemaking and the addition in briquettes produced for the recovery of iron bearing rest products. The challenge with biomass in cokemaking is its low density and high reactivity which decrease the coke yield and coke strength at the same time that it increases the coke reactivity. The coke quality has to be kept at sufficient quality in order to avoid effects on productivity and process stability in the blast furnace. The addition of biomass in briquettes is limited due to the low density of the biomass which may affect the strength of the briquettes. The effect of the addition of sawdust in coke and briquettes has been studied to understand the effect on reaction behaviour of bio-coal. Heat-treatment of sawdust with high volatile coal was performed in order to achieve a coating of coal on the sawdust surface and get less reactive sawdust. Torrefied sawdust contained 23 wt. % fixed carbon while the pre-treatment of sawdust with high volatile coal increased the content to about 60 wt. %. Pre-treated sawdust was added to coal blend for coke making and briquettes containing iron oxide. The pre-treated sawdust was added to five coal blends for coke production, the contents were 5, 10 and 20 wt. %, and a base blend was used as reference. Coke reactivity, chemical composition and cold compression strength in coke were studied. This work resulted in an improved bulk density; up to 20 wt. % pre-treated sawdust could be added to the coal blend and still keep a bulk density of 800 kg/m3. The coke yields in cokes with pre-treated sawdust were comparable to the coke reference. The temperature at which carbon in coke began to be consumed was slightly higher in coke containing sawdust treated with 50 wt. % high volatile coal. It was estimated that the CO2 emission from fossil coal could be reduced with 8.6 % per ton hot metal (THM) with the addition of 10 wt. % pre-treated sawdust to coal blends for cokemaking. The addition of 20 wt. % pre-treated sawdust could reduce the CO2 emission with 10% per THM. In addition, two different mixes of briquettes were produced, one with torrefied sawdust and one with pre-treated sawdust. The chemical composition and reduction of iron oxides in briquettes was also studied and evaluated. Briquettes with treated sawdust were more compact, i.e. had a higher density than briquettes containing torrefied sawdust. The amount of hematite that could be added to the briquette mixes was 0.107 moles in briquettes with torrefied sawdust and 0.112 moles in briquettes with pre-treated torrefied sawdust.
Koldioxidutsläppet till atmosfären orsakar idag problem runt om i världen. I Sverige bidrar stålproduktionen avsevärt till koldioxidutsläppet. Stålindustrin har som en utmaning att förbättra de metallurgiska processerna för att sänka utsläppet av koldioxid. Ett sätt att sänka koldioxidutsläppen är att minska påverkan genom att använda förnybara kolkällor. Masugnsprocessen är en kontinuerlig reduktionsprocess för råjärnframställning och en av processerna där det används reduktionsmedel från fossila kolkällor. Råmaterial som järnmalm, koks och slaggformare chargeras på toppen av ugnen medan syrgasberikad blästerluft och pulveriserat kol injiceras i botten av ugnen genom masugnens formor. De gaser som produceras vid förbränning stiger upp genom beskickningen upp till ugnens topp. Vid förgasning av kol bildas kolmonoxid som är den reducerande gasen, den möjliggör reduktionen av järnoxider vid framställning av råjärn. Torrefierad biomassa kan delvis ersätta fossilt kol i kolblandningarna för kokstillverkning, i kolinjektionen och i briketter. Syftet med detta projekt var att maximera mängden tillsatt biomassa i kolblandningarna för kokstillverkning och i briketter för återvinning av järnbärande restprodukter. Utmaningen med biomassa i kokstillverkningen är den höga reaktiviteten och den låga densiteten av kol, vilket resulterar i låg koksutbyte när den tillsätts i kolblandningar. Biomassa innehåller också en högt halt flyktiga ämnen vilket resulterar i koks med låg hållfasthet och hög reaktivitet. Kokskvalitén måste behållas för att undvika processvariationer i masugnen. Tillsatsen av biomassa i briketter, är begränsat då biomassa kan påverka briketternas hållfasthet. Effekten av tillsatsen av biomassa i koks och briketter har studerats för att kunna förstå reaktionsbeteendet i dessa när torrefied sågspån och förbehandlat sågspån med hög fluiditetskol har tillsatts till blandningarna. Värmebehandling av torrifierat sågspån med en hög fluiditeteskol gjordes för att uppnå en mindre reaktiv biomassa. Torrifierat sågspån innehöll 22.9 viktsprocent kol, förbehandlingen av sågspån med hög fluiditetskol ökade halten till cirka 60 viktsprocent. Den behandlade sågspånen tillsattes till fem kolblandningar för koksframställning, 5, 10 och 20 viktprocent tillsattes till en bas blandning som användes referens. Koksreaktiviteten, kemisk sammansättning och hållfasthet i koks studerades. Arbetet resulterade i en förbättrad bulkdensitet då upp till 20 viktprocent förbehandlad biomassa kunde tillsättas i kolblandningen och fortfarande behålla en bulkdensitet på 800 kg/m3. Koksutbytet i alla koks med förbehandlat sågspån var jämförbart med koksreferensen. Temperaturen där kemisk kol i koks började förbrukas, var något högre i koks som innehöll sågspån med 50 viktsprocent hög fluiditetskol. Koldioxidutsläppen från fossilt kol per ton råjärn (THM) uppskattades att vara 8,6 % lägre med tillsatsen av 10 viktprocent förbehandlat sågspån i kolblandningar för kokstillverkning. Tillsatsen av 20 viktprocent skulle innebära en minskning på 10 % per ton råjärn. Briketter med två olika blandningar framställdes, en blandning med torrifierat sågspån och en blandning med behandlat sågspån. Briketterna karakteriserades genom att analysera den kemiska sammansättningen och reduktionen av järnoxider i termisk reducerade briketter. Briketter med behandlat sågspån var mer kompakta, d.v.s. hade en högre densitet än briketter som innehöll torrifierad sågspån. Mängden hematit som kunde tillsättas i mixen med torrifierad sågspån var 0.107 mol, medan i mixen med förbehandlat sågspån 0.112 mol kunde tillsättas.
Bio4metals
CAMM

In Underwater Acoustic Sensor Networks (UWASNs), cameras have recently been deployed for enhanced monitoring. However, their use has faced several obstacles. Since video capturing and processing consume significant amounts of camera battery power, they are kept in sleep mode and activated only when ultrasonic sensors detect a target. The present study proposes a camera relocation structure in UWASNs to maximize the coverage of detected targets with the least possible vertical camera movement. This approach determines the coverage of each acoustic sensor in advance by getting the most applicable cameras in terms of orientation and frustum of camera in 3-D that are covered by such sensors. Whenever a target is exposed, this information is then used and shared with other sensors that detected the same target. Compared to a flooding-based approach, experiment results indicate that this proposed solution can quickly capture the detected targets with the least camera movement.

Concentrated solar power (CSP) is a fast-growing technology for electricity production. With mirrors (heliostats) irradiation of the sun is concentrated onto a receiver run through by a heat transfer fluid (HTF). The fluid by that reaches high temperatures and is used to drive a steam turbine for electricity production. A CSP power plant is most often coupled with an energy storage unit, where the HTF is stored before it is dispatched and used to generate electricity. Electricity is most often sold at an open market with a fluctuating spot-prices. It is therefore of high importance to generate and sell the electricity at the highest paid hours, increasingly important also since the governmental support mechanisms aimed to support renewable energy production is faded out since the technology is starting to be seen as mature enough to compete by itself on the market. A solar power plant thus has an operational protocol determining when energy is dispatched, and electricity is sold. These protocols are often pre-defined which means an optimal production is not achieved since irradiation and electricity selling price vary. In this master thesis, an optimization algorithm for electricity sales is designed (in MATLAB). The optimization algorithm is designed by for a given timeframe solve an optimization problem where the objective is maximized revenue from electricity sales from the solar power plant. The function takes into consideration hourly varying electricity spot price, hourly varying solar field efficiency, energy flows in the solar power plant, start-up costs (from on to off) plus conditions for the logic governing the operational modes. Two regular pre-defined protocols were designed to be able to compare performance in a solar power plant with the optimized dispatch protocol. These three operational protocols were evaluated in three different markets; one with fluctuating spot price, one regulated market of three fixed price levels and one in spot market but with zero-prices during sunny hours. It was found that the optimized dispatch protocol gave both bigger electricity production and revenue in all markets, but with biggest differences in the spot markets. To evaluate in what type of powerplant the optimizer performs best, a parametric analysis was made where size of storage and power block, the time-horizon of optimizer and the cost of start-up were varied. For size of storage and power block it was found that revenue increased with increased size, but only up to the level where the optimizer can dispatch at optimal hours. After that there is no increase in revenue. Increased time horizon gives increased revenue since it then has more information. With a 24-hour time horizon, morning price-peaks will be missed for example. To change start-up costs makes the power plant less flexible and with fewer cycles, without affect income much.
Koncentrerad solkraft (CSP) är en snabbt växande teknologi för elektricitets-produktion. Med speglar (heliostater) koncentreras solstrålar på en mottagare som genomflödas av en värmetransporteringsvätska. Denna uppnår därmed höga temperaturer vilket används för att driva en ångturbin för att generera el. Ett CSP kraftverk är oftast kopplat till en energilagringstank, där värmelagringsvätskan lagras innan den används för att generera el. El säljs i de flesta fall på en öppen elmarknad, där spotpriset fluktuerar. Det är därför av stor vikt att generera elen och sälja den vid de timmar med högst elpris, vilket också är av ökande betydelse då supportmekanismerna för att finansiellt stödja förnybar energiproduktion används i allt mindre grad för denna teknologi då den börjar anses mogen att konkurrera utan. Ett solkraftverk har således ett driftsprotokoll som bestämmer när el ska genereras. Dessa protokoll är oftast förutbestämda, vilket innebär att en optimal produktion inte fås då exempelvis elspotpriset och solinstrålningen varierar. I detta examensarbete har en optimeringsalgoritm för elförsäljning designats (i MATLAB). Optimeringsscriptet är designat genom att för en given tidsperiod lösa ett optimeringsproblem där objektivet är maximerad vinst från såld elektricitet från solkraftverket. Funktionen tar hänsyn till timvist varierande elpris, timvist varierande solfältseffektivitet, energiflöden i solkraftverket, kostnader för uppstart (on till off) samt villkor för att logiskt styra de olika driftlägena. För att jämföra prestanda hos ett solkraftverk med det optimerade driftsprotokollet skapades även två traditionella förutbestämda driftprotokoll. Dessa tre driftsstrategier utvärderades i tre olika marknader, en med ett varierande el-spotpris, en i en reglerad elmarknad med tre prisnivåer och en i en marknad med spotpris men noll-pris under de soliga timmarna. Det fanns att det optimerade driftsprotokollet gav både större elproduktion och högre vinst i alla marknader, men störst skillnad fanns i de öppna spotprismarknaderna. För att undersöka i vilket slags kraftverk som protokollet levererar mest förbättring i gjordes en parametrisk analys där storlek på lagringstank och generator varierades, samt optimerarens tidshorisont och kostnad för uppstart. För lagringstank och generator fanns att vinst ökar med ökande storlek upp tills den storlek optimeraren har möjlighet att fördela produktion på dyrast timmar. Ökande storlek efter det ger inte ökad vinst. Ökande tidshorisont ger ökande vinst eftersom optimeraren då har mer information. Att ändra uppstartkostnaden gör att solkraftverket uppträder mindre flexibelt och har färre cykler, dock utan så stor påverkan på inkomst.

Includes abstract.
Includes bibliographical references (leaves [157]-178).
The aims of this study were to (a) explore health literacy and information recall/memory of clients receiving Speech-Language Pathology treatment in Cape Town, and (b) to explore ways of maximising these factors in clients with dysphagia, voice disorders (including laryngectomies) and cleft lip and/or palate.

碩士
國立中山大學
電機工程學系研究所
102
In a wireless sensor network (WSN), sensors are generally battery-powered. Hence it is essential to design a good power saving protocol, which operates at the medium access control (MAC) layer, to prolong the lifetime of a WSN. Recently, quorum systems are heavily utilized to design power saving protocols for a WSN where each senor wakes up in time frames associating with a quorum. In a quorum system, any two quorums always overlap. However, existing quorum-based power saving protocols are far from optimal in terms of duty cycle and configurability. Especially, we notice that in a corona-based WSN, there is no need to insist on the overlap of awake time frames between every pair of sensors. By only guaranteeing the overlap of awake time frames between sensors in neighboring coronas, the whole WSN can still function well since each sensor needs to rely on merely the sensors in the inner adjacent corona to forward data to the sink. On the basis of this principle, we design an optimal and maximized configurable power saving protocols, called Green-MAC, for a corona-based WSN. More specifically, given the maximum cycle length n_max, in Green MAC, the duty cycle of each sensor is only O(1 ⁄ n_max ), and the number of configurable duty cycles can be O(n_max ⁄ ln n_max ). These results reach the theoretically asymptotic optimum. To illuminate the power of configurability, we focus on the event detection and reporting applications, and show how to configure the cycle length for sensors in each corona such that the source-to-sink delay requirement can be satisfied with a predefined probability. Extensive simulation results demonstrate that Green-MAC is much superior to existing quorum-based power saving protocols in terms of throughput, lifetime, and data delay dropped ratio.

博士
大同大學
機械工程學系(所)
103
Because portable electronic devices are popular, a durable electrical power for these devices is necessary. However, there is a problem of electrical exhaust during a prolonged use. So as to provide sufficient and continuous electrical power, interest in developing portable energy harvesters with a spring-mass system is raising. As can be seen, application of the cantilever-beam electrical generator is limited to small vibrations at a higher frequency and is used within small systems such as the MEMS. A structure with a spring-mass system is often used to extract energy from a vibration system of lower frequencies and larger displacement. In order to find an optimal mechanism for the one-mass energy harvester that produces maximal electrical power, the assessment of optimal electrical power with ten design factors is presented. Concerning the geometric allocation, four parameters ( : the magnet diameter; : the magnet height; : the system damping ratio; and : the coil’s revolution number) are adopted for maximization of electrical power. Also, considering the buckling effect for a spring that will consume the vibrational energy and damage the spring, a critical deflection is included in the optimization using a penalty factor of PN1. Similarly, concerning the influence of fatigue induced by fluctuating stress, the safety factor will be rechecked using a penalty factor PN2 in the SA optimization. Considering the portable energy harvester which can be easily carried put inside a backpack and generates great electricity while walking, three kinds of one-mass portable energy harvesters with swinging type (prototype I, prototype II, and prototype III) are also developed and experimentally tested. Results reveal that the electrical energy reaching 0.25 W is generated from the energy harvester (prototype III) by extracting kinetic energy produced by walking. Moreover, because only a resonating vibration will be induced for a one-mass vibrating system, the energy extracted from the one-mass vibrational system was limited to vibration with one forcing frequency. Therefore, in order to extract more vibrational energy from equipment having multi-tone forcing vibration, the development of a multi-mass energy harvester used to extract the vibrational energy at the multi-tone resonating frequencies is essential. In order to improve output electricity, a vibration-based energy harvester with a two-mass vibrational system is also proposed. To maximize the extracted energy, two resonant frequencies of the two-mass vibrational system will be simultaneously tuned as two external vibrating frequencies emitted from the vibrational source. Eight kinds of design parameters used in tuning the system’s natural frequencies are adopted. The optimization of above one-mass and two-mass electromagnetic energy harvesters is performed by using the simulated annealing (SA) method. Results reveal that the electrical power is optimally extracted at the two primary forcing frequencies of the vibrational equipment. Furthermore, it is obvious that the induced electrical power of the two-mass energy harvester will be superior to that of the one-mass energy harvester.

博士
國立交通大學
統計學研究所
96
Positron emission tomography (PET) can provide in vivo, quantitative and functional information for the diagnosis of functional diseases; however, PET image quality is highly dependent on a reconstruction algorithm. Iterative algorithms, such as the maximum likelihood expectation-maximization (MLEM) algorithm, are rapidly becoming the standards for image reconstruction in emission tomography. The conventional MLEM algorithm utilized the Poisson model, which is no longer valid for delay-subtraction after random correction. This study was undertaken to overcome this problem. The MLEM algorithm is adopted and modified to reconstruct microPET images with random correction from the joint Poisson model of prompt and delay sinograms; this reconstruction method is called PDEM. The proposed joint Poisson model preserves Poisson properties without increasing the variances of estimates associated with random correction. The coefficients of variation (CV) and full width at half-maximum (FWHM) values were utilized to compare the quality of reconstructed microPET images of physical phantoms acquired by filtered backprojection (FBP), ordered subsets expectation-maximization (OSEM) and PDEM approaches. Experimental and simulated results demonstrated that the proposed PDEM method yielded better image quality results than the FBP and OSEM approaches. The segmentation of 3D microPET image is one of the most important issues in tracing and recognizing the gene activity in vivo. In order to discover and recover the activity of gene expression, reconstruction techniques with higher precision and fewer artifacts are necessary. To improve the resolution on microPET images, the PDEM method is applied. In addition, the advanced statistical technique based on the mixture model is developed to segment the reconstructed images. In this study, the new proposed method is evaluated with simulation and empirical studies. The performance shows that the proposed method is promising in practice. The segmentation of cDNA microarray spots is essential in analyzing the intensities of microarray images for biological and medical investigations. In this work, the nonparametric method of kernel density estimation is applied to segment two-channel cDNA microarray images. This approach successfully groups pixels into foreground and background. The segmentation performance of this model is tested and evaluated by sixteen microarrays. Specifically, spike genes with various levels of contents are spotted in a microarray to examine and evaluate the accuracy of the segmentation results. Duplicated design is implemented to evaluate the accuracy of the model. Swapped experiments of microarray dyes are also implemented. Results of this study demonstrate that this method can cluster pixels and estimate statistics regarding spots with high accuracy.