Letteratura scientifica selezionata sul tema "SELGEM (Computer program)"

Briefing and the design brief seldom attract attention in architectural computerization. Nevertheless, the computer offers us substantial opportunities for the explicit, effective, and efficient treatment of information in both briefing and designing. The chapter introduces the approach underlying the use of computers in briefing, from the structure of a brief and the terminology used in the book to the range of relevant computer programs.

At the Massachusetts Institute of Technology in the 1950s, some of the brightest students seldom attended classes. Instead they loitered around the Tech Model Railroad Club. The most brilliant were tapped to join the Signals and Power Committee, which rigged ever more elaborate systems of programmable track switches using nothing more sophisticated than telephone relays. Taking pride in their ad hoc wiring, which ignored all conventions of electrical engineering, they referred to themselves as hackers. Nothing was impossible for them; nothing was off limits. When MIT acquired its first computer in 1956, they infiltrated the control room, where they coerced the electronics to do tricks unintended by the manufacturer, using sine and cosine routines to code the first digital computer game. As computers became more common, so did hacking. To program home computers in the 1970s no longer required the imaginative genius of the MIT Signals and Power Committee, and by the 1980s self-professed hackers ranged from professional software developers to adolescent cyberpunks. The latter proved considerably more interesting to the public, riveted by their ability to torment corporations and governments from their bedrooms. “A hacker—computer jargon for an electronic eavesdropper who by-passes computer security systems—yesterday penetrated a confidential British Telecom message system being demonstrated live on BBC-TV,” reported the Daily Telegraph in a typical news story of 1983, the year that War Games hit the big screen. Old-school Signals and Power hackers fought valiantly against this linguistic turn, insisting that the young punks were crackers rather than hackers, but the media ignored the distinction, leading most new-school professionals to head off confusion by blandly presenting themselves as computer scientists or software engineers or information technology specialists. Aside from the occasional insider reference—ITs who troubleshoot security systems were sometimes known as “white-hat” hackers— the criminal connotation seemed permanent. Then in 2004 a Silicon Valley technology writer named Danny O’Brien gave a forty-five-minute lecture at the O’Reilly Emerging Technology Conference titled “Life Hacks: Tech Secrets of Overprolific Alpha Geeks.” Within a year technophiles worldwide, from computer scientists to iPhone addicts, were striving to become hackers again.

The nuclear waste programs of the United States and other countries have forced geologists to think specifically about probabilities of natural events, because the legal requirements to license repositories mandate a probabilistic standard (US EPA, 1985). In addition, uncertainties associated with these probabilities and the predicted performance of a geologic repository must be stated clearly in quantitative terms, as far as possible. Geoscientists rarely have thought in terms of stochasticity or clearly stated uncertainties for their results. All scientists are taught to acknowledge uncertainty and to specify the quantitative uncertainty in each derived or measured value, but this has seldom been done in geology. Thus, the nuclear waste disposal program is forcing us to do now what we should have been doing all along: acknowledge in quantitative terms what uncertainty is associated with each quantity that is employed, whether deterministically or probabilistically. Uncertainty is a simple concept ostensibly understood to mean that which is indeterminate, not certain, containing doubt, indefinite, problematical, not reliable, or dubious. However, uncertainty in a scientific sense demonstrates a complexity which often is unappreciated. Some types of uncertainty are difficult to handle, if they must be quantified, and a completely satisfactory treatment may be impossible. Initially, only uncertainty associated with measurement, was quantified. The Gaussian, or normal, probability density function (pdf) was recognized by Carl Friedrich Gauss as he studied errors in his measurements two centuries ago and developed a theory of errors still being used today. This was the only type of uncertainty that scientists acknowledged until Heisenberg stated his famous uncertainty principle in 1928. As information theory evolved during and after World War II, major advances were made in semantic uncertainty. Today, two major types of uncertainty are generally recognized (Klir and Folger, 1988): ambiguity or nonspecificity and vagueness or fuzziness. These can be subdivided further into seven types having various measures of uncertainty based on probability theory, set theory, fuzzy-set theory, and possibility theory.

Hepatocellular carcinoma arises commonly on the background of liver cirrhosis. Patients presenting with clinical symptoms have advanced stage and often are unsuitable for curative therapies. Diagnosis of hepatocellular carcinoma is commonly performed by multiphase computed tomography (CT) and / or magnetic resonance imag¬ing scans (MRI). Contrast enhanced ultrasound and MRI with hepatobiliary contrast agents are better in characterizing small lesions. Tumor markers play an adjunct role in diagnosis. For HCC in cirrhotic liver biopsy is seldom required and diagnosis is based on typical imaging features of non-rim arterial phase hyperenhancement and washout on delayed phase and pseudocapsule appearance. This is due to differential blood supply of liver parenchyma, regenerative nodules and tumor. Biopsy is only required in noncirrhotic liver, vascular liver diseases, atypical imaging features. Surveillance programs involving high risk groups can help in early detection of lesions which are amenable for curative therapies. Biannual ultrasound with or without alfa fetoprotein are commonly used surveillance tests. Multidisciplinary teams provide platform for care coordination, reassessments of clinical course, and fine changes in treatment plans required for management of this complex group of patients.

It is well known that changes in soil degree of saturation have an important influence on mechanical soil properties. Decreasing suction in soil leads to an increase of specific weight and to a decrease of stiffness and strength. These mechanical changes may have an important influence on underground works, particularly on subsurface tunnels. In fact, decreasing soil cohesion due to saturation reduces arching effects above tunnels. Recent developments in unsaturated soil behaviour include numerical models coupling hydro-mechanical phenomena and considering elastoplastic constitutive laws. However, these techniques are seldom used in practical applications. This paper presents a methodology to compute stress and strain changes in a tunnel lining due to changes in soil saturation, using relatively conventional tools. The motivation of this work comes from a real case in Barcelona, where a Metro tunnel received an increment of loading due to loss of cohesion of upper layers after irrigation. The Finite Element programme “PLAXIS” was used. The paper concludes that the effect of soil saturation changes on underground structures can be assessed by using conventional Finite Element codes, if the variation of stiffness and strength with suction is previously known. The analyses presented in the paper show that changes in density and stiffness due to saturation have little influence on the stresses in the sidewalls of a subsurface tunnel. However, reduction of cohesion due to suction changes may reduce arching effects above the tunnel and would generate high stresses in the tunnel lining.

Abstract This paper presents results of developing the Informational and Computational System for CFD Researchers. It is the second generation of SELIGER: System of Embedded-Linked Information and Graphics for Engineers and Researchers. The main goal of the system is a support of CFD and related sciences working in the net environment. Modification of the network prototype is connected with server’s database modernization to provide stable working and fast accessing to server. Java-based applets provide an effective front-end interface to the remote CFD solvers. The network programs support an

Design across the curriculum has been a cornerstone of mechanical engineering education for well over a decade. The movement was an attempt to balance the tendency of most programs to over-emphasize engineering science. Over the course of that decade, many public universities have undergone a 7%–10% reduction in the number of credits required for graduation; usually in response to legislative pressure or competitive market conditions. In some instances, these reductions were not reflected in the general education content. Although the number of technical electives within the curriculum may hav