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by Lee Kwan-Chuen. / Title also in Chinese. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1989. / Bibliography : leaves 86-88.

Thesis (M.S.)--University of Michigan, 1963.

A evaluation of Ruby on Rails regarding performance.

The thesis presents the Ruby language and deals with the idea of including this language in the teaching of computer science at the University of Economics in Prague (UEP). In the beginning of their studies, all students have to complete two compulsory science subjects related to programming, which is the first experience with programming for many of them. Currently, the primary programming language being taught is Java. This work aims to present Ruby language, as an alternative to currently taught Java or at least as a language which the students could continue with after studying Java. In the introduction of the thesis the reader gets familiar with the history of language with its philosophy, which stood at the birth of Ruby and the basic concepts on which it is based. Next there are presented the basic constructs and syntax which are necessary to understand the final part of the paper, which discusses the different programming techniques that can be used in Ruby. The final chapter highlights the features of Ruby, for which it would be appropriate to include Ruby in the languages taught at UEP. These include especially clear and concise syntax, possibility to use different programming paradigms and creating internal DSL. The practical outcome of the whole work is a web application that offers an interactive form of the work itself. It is possible to browse the whole work in the internet and all mentioned examples of program code can be immediately tested in practice. The application outlines possible direction which can teaching programming languages take.

The Ruby programming language is dynamically typed, uses dynamic and late bound dispatch for all operators, method calls and many control structures, and provides extensive metaprogramming and introspective tooling functionality. Unlike other languages where these features are available, in Ruby their use is not avoided and key parts of the Ruby ecosystem use them extensively, even for inner-loop operations. This makes a high-performance implementation of Ruby problematic. Existing implementations either do not attempt to dynamically optimise Ruby programs, or achieve relatively limited success in optimising Ruby programs containing these features. One way that the community has worked around the limitations of existing Ruby implementations is to write extension modules in the C programming language. These are statically compiled and then dynamically linked into the Ruby implementation. Compared to equivalent Ruby, this C code is often more efficient for computationally intensive code. However the interface that these C extensions provides is defined by the non-optimising reference implementation of Ruby. Implementations which want to optimise by using different internal representations must do extensive copying to provide the same interface. This then limits the performance of the C extensions in those implementations. This leaves Ruby in the difficult position where it is not only difficult to implement the language efficiently, but the previous workaround for that problem, C extensions, also limits efforts to improve performance. This thesis describes an implementation of the Ruby programming language which embraces the Ruby language and optimises specifically for Ruby as it is used in practice. It provides a high performance implementation of Ruby's dynamic features, at the same time as providing a high performance implementation of C extensions. The implementation provides a high level of compatibility with existing Ruby implementations and does not limit the available features in order to achieve high performance. Common to all the techniques that are described in this thesis is the concept of specialisation. The conventional approach taken to optimise a dynamic language such as Ruby is to profile the program as it runs. Feedback from the profiling can then be used to specialise the program for the data and control flow it is actually experiencing. This thesis extends and advances that idea by specialising for conditions beyond normal data and control flow. Programs that call a method, or lookup a variable or constant by dynamic name rather than literal syntax can be specialised for the dynamic name by generalising inline caches. Debugging and introspective tooling is implemented by specialising the code for debug conditions such as the presence of a breakpoint or an attached tracing tool. C extensions are interpreted and dynamically optimised rather than being statically compiled, and the interface which the C code is programmed against is provided as an abstraction over the underlying implementation which can then independently specialise. The techniques developed in this thesis have a significant impact on performance of both synthetic benchmarks and kernels from real-world Ruby programs. The implementation of Ruby which has been developed achieves an order of magnitude or better increase in performance compared to the next-best implementation. In many cases the techniques are 'zero-overhead', in that the generated machine code is exactly the same for when the most dynamic features of Ruby are used, as when only static features are used.

<p> Following the introduction to the field of lasers and the theories of laser oscillations in the light output, it is pointed out that calculations involving existing theories yield oscillation periods in excess of the period observed for our crystal. To account for this disagreement, the thesis proposes the inclusion of the additional loss terms of scatter and diffraction augmenting the transmission loss. The theory of Birnbaum Stocker and Welles (BSWl) is extended to include these additional loss mechan- isms and the oscillation period predicted, using the mea- sured values of these parameters is in good agreement with the. observed oscillation period. </p> / Thesis / Master of Science (MSc)

Objective: To characterize the effect of the Ruby Joint Stabilization System (Ruby) on the motion of the cranial cruciate ligament (CrCL) deficient stifle. To compare the motion with the Ruby to that of the CrCL-intact and CrCL-deficient stifle. Study Design: Each canine pelvic limb was mounted in a loading jig under 30% body weight. Motion data was collected using an electromagnetic tracking system at stifle angles of 125o, 135o and 145o with the CrCL-intact, CrCL-deficient and the Ruby applied. Results: Total translation of the CrCL-deficient stifle following the Ruby was reduced, but remained greater than the CrCL-intact stifle at angles of 125o, 135o and 145o. Internal rotation of the Ruby groups was greater than the CrCL-intact group at 145o, but not 125o and 135o. Varus motion of the Ruby group was decreased compared to the CrCL-deficient group, but increased compared to the CrCL-intact group at angles of 125o, 135o and 145o. Conclusion: Total translation and internal rotation of the CrCL-deficient stifle following the Ruby differed from that of the CrCL-intact stifle. However, the Ruby reduced total translation and internal rotation of the tibia relative to the femur in the CrCL-deficient stifle to levels that may yield clinically acceptable results. / Master of Science / Cranial cruciate ligament disease is a common pathology of the canine stifle. Loss of this ligament results in instability of the stifle that results in pain and osteoarthritis, and can lead to damage of other intra-articular structures like the menisci. An abundant number of surgical procedures are described, with the goal of surgery being the restoration of normal stifle stability and function. A common surgical procedure for treatment is the lateral suture technique, which is an extracapsular method of stabilization. This procedure faces many complications; however, it remains a popular choice of stabilization due to its lower cost and less invasive nature. The Ruby Joint Stabilization procedure is a method of extracapsular repair that aims to restore stifle stability and circumvent several complications that plague the lateral suture. This cadaveric study sought to investigate how stifle motion of the normal canine stifle compared to that of the cranial cruciate ligament deficient stifle with the Ruby Joint Stabilization System applied. The results of this investigation demonstrated that the Ruby Joint Stabilization System adequately restored stifle motion to a level that could yield clinically acceptable results, as was demonstrated in a previously published clinical investigation of this technique.

This thesis aids at comparing two frameworks based on Python and Ruby used for agile web development. Besides the basic description, history and philosophy of both Django and Ruby on Rails, all criteria used for their evaluation are laid down, described and put into wider context. In addition, the implementation of the MVC architecture in both frameworks is described along with the basic project structure and tools available.

<p>Skriptspråk har under det senaste decenniet fått en ökad spridning, både gällande användare</p><p>och gällande användningsområden. Från att huvudsakligen ha använts till enklare dagliga</p><p>administratörsuppgifter används idag skriptspråken inom många områden där tidigare enbart</p><p>systemspråk var ett alternativ. Denna uppsats undersöker och granskar fem skriptspråk: PHP,</p><p>Perl, Ruby, Tcl och PostScript. Målet är att undersöka språkens egenskaper och se på</p><p>skillnader språken emellan. Vi jämför också skriptspråken mot systemspråket C, som dock</p><p>inte granskas för sig. Vi utför ett test där quicksort-algoritmen används för att sortera ett antal</p><p>element som läses in från fil. Ett testskript skrivs i varje språk, och dess effektivitet och</p><p>expressivitet jämförs.</p><p>Vi kommer i denna uppsats fram till att definitionen för skriptspråk, och det som skiljer</p><p>skriptspråk från systemspråk, är skriptspråkens avsaknad av ett separat kompileringssteg. En</p><p>annan viktig aspekt är skriptspråkens användning av dynamisk typbindning för variabler. De</p><p>tester vi gjort visar att inget av skriptspråken kan mäta sig med systemspråket C vad gäller</p><p>exekveringstid, däremot är de bättre gällande expressivitet. Av skriptspråken är Perl det språk</p><p>som är snabbast och PostScript det språk som är långsammast.</p> / <p>During the last decade, scripting languages have seen an increase in both number of users and</p><p>areas of development. Earlier, scripting languages were mainly used for everyday system</p><p>administration tasks. Nowadays, scripting languages are used in areas where previously only</p><p>system languages were an alternative. In this dissertation, five scripting languages are</p><p>compared and reviewed. The languages are: PHP, Perl, Ruby, Tcl, and PostScript. The goal is</p><p>to examine characteristics of the languages and illustrate the differences between them. We</p><p>also compare the scripting languages against the system language C, which is not examined in</p><p>this dissertation. We perform a test where the quicksort algorithm is used to sort a number of</p><p>elements which are read from file. A test script is written in every language, and their</p><p>efficiency and expressiveness are compared.</p><p>In this dissertation we come to the conclusion that the definition of scripting languages, and</p><p>the main difference between scripting languages and system languages, is the absence of a</p><p>separate compiling stage for scripting languages. We also consider the use of dynamic typing</p><p>regarding variables to be an important aspect of scripting languages. The tests have shown</p><p>that scripting languages can not compete with the system language C regarding efficiency of</p><p>execution, but the scripting languages have a higher level of expressiveness. Perl is fastest</p><p>among the scripting languages and PostScript is the slowest.</p>