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Analysis of cOVID‐19 Mathematical and Software Models: Or How NOT to Set Up a Softward Project

Wilmott 2020年第110期2020卷 66-71页

This report discusses the open‐source software that implements the cOVID‐19 model in [1] (announced March 16, 2020), led by Dr. Neil Ferguson of Imperial college London (IcL). My personal interest was to investigate how the model was implemented after having seen it described as a system of ordinary differential equations (ODEs) on BBc News on March 17, 2020. Anecdotal evidence suggests that the original program (written in c) is at least 20 years old and it is undocumented (nothing new in the software world; the programmers in this case probably thought it was not necessary to write readable and maintainable software). Furthermore, all the 15,000 lines of code were in a single file (sometimes called balls of mud). On April 22, 2020 a modified version (called 0.7.0, seemingly produced by Microsoft) appeared consisting of approximately 12 separate source files. This is the version of the program that we review in this article. We do not investigate the fixes that have been made between April 22 and the time of writing of this report. Finally, we note that version 0.7.0 is not an implementation of the ODEs that were announced on BBc News with great aplomb on the evening of Saint Patrick's Day 2020. For a discussion of ODEs in epidemiology, see [2]. Before I discovered that the IcL model was not ODE‐based (seemingly contradicting the BBc announcement) I solved the MSEIR (iMmune, Susceptible, Exposed, Infective, Recovered) ODE model numerically in c++. The system of equations is relatively benign and we used the c++ Boost odeint library to solve them. (A word of advice: it is tempting to use the Euler method but don't use it, not even for producing cute S‐curves in your blogs.)Summarizing, this report is a critique of the quality of 0.7.0 code based on my experience, background, and how I view software. I was unable to analyze the underlying mathematical model because it is not documented and the code is unreadable. However, I do have something to say about the (lack of

关键词： c language big balls of mud software crisis software quality metrics random number generation parallel code (speedup, race conditions) software maintenance defined software process

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***: visualizing c programs on web browsers for novices

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HELIYON 2020年第4期6卷 e03806-e03806页

作者： Ishizue, Ryosuke Sakamoto, Kazunori Washizaki, Hironori Fukazawa, Yoshiaki Waseda Univ Dept Sci & Engn Tokyo Japan Natl Inst Informat Tokyo Japan WillBooster Inc Tokyo Japan SYST INFORMAT CO LTD Tokyo Japan eXmot Co Ltd Tokyo Japan

Many researchers have proposed program visualization tools for memory management. Examples include state-of-the-art tools for c languages such as Seec and Python Tutor (PT). However, three problems hinder the use of these and other tools: capability (P1), installability (P2), and usability (P3). (P1) Tools do not fully support dynamic memory allocation or File Input / Output (I/O) and Standard Input. (P2) Novice programmers often have difficulty installing Seec due to its dependence on clang and setting up an offline environment that uses PT. (P3) Revisualization of the modified source code in Seec requires several steps. To alleviate these issues, we propose a new visualization tool called *** (***). ***, which is designed for novice c language programmers to provide solutions (S1-3) for P1-3. S1 offers complete support for dynamic memory allocation, standard I/O, and file I/O. S2 involves installation in a user web browser. This system is composed of JavaScript programs, including c language execution functions. S3 reduces the steps required for revisualization. To evaluate ***, we conducted two experiments. The first experiment found that students using PVc solved a set of four programming tasks on average 1.7-times faster and with 19% more correct answers than those using Seec. The second experiment found that *** has a visualization performance equivalent to PT, and that *** is more effective than existing general debugging tools for novices to understand programs in cases where the values of important variables change and the control flow is complicated.

关键词： Science c language Browser application Visualization

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Square Matrix Multiplication Using cUDA on GP-GU 5

Square Matrix Multiplication Using CUDA on GP-GU

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5th Information Systems International conference (ISIcO) on Role of Information Systems in Industry 4.0

作者： Jimale, Ali Olow Ridzuan, Fakhitah Zainon, Wan Mohd Nazmee Wan Univ Sains Malaysia Sch Comp Sci George Town 11800 Malaysia SIMAD Univ Fac Comp Mogadishu Somalia

This paper focuses on matrix multiplication algorithm, particularly square parallel matrix multiplication using computer Unified Device Architecture (cUDA) programming model with c programming language. Matrix multiplication is under the list of time-consuming problems that require s huge computational resources to improve its speedup. As many studies have shown, it is not easy to achieve high performance speedup in sequential matrix multiplication algorithm using larger input. The emphasis of this study is to propose a parallel algorithm to calculate the product of two square matrices with improved speedup performance compared to the sequential and OpenMP algorithms. In this research, biruni (super machine workstation) in the School of computer Sciences, USM, Malaysia with General Purpose Graphics Processing Unit (GP-GU) was used to parallelize the matrix product algorithm. A comparison between parallel OpenMp versions and sequential algorithm with the proposed cUDA based algorithm of this research was carried out to evaluate the speedup performance of the proposed parallel cUDA based algorithm. The overall results show that cUDA based parallel matrix multiplication is approximately 400 times faster than sequential matrix multiplication and 4 times faster than OpenMp matrix multiplication algorithms, respectively. Therefore, the proposed parallel algorithm can help the researchers working with matrix multiplication application problems. It can also help mathematicians to easily calculate the product of any two matrices and obtain the result in a shorter time. (c) 2019 The Authors. Published by Elsevier B.V.

关键词： cUDA GPGU parallelization c language Matrix multiplication

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ALPAcA: A Large Portfolio-based Alternating conditional Analysis 19

ALPACA: A Large Portfolio-based Alternating Conditional Anal...

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IEEE/AcM 41st International conference on Software Engineering - Software Engineering in Practice (IcSE-SEIP)

作者： Gerrard, Mitchell J. Dwyer, Matthew B. Univ Virginia Charlottesville VA 22903 USA

ISBN: (纸本)9781728117645

Program analysis tools typically compute either may or must information. By accumulating both kinds of information computed with respect to different portions of a program's state space, it is possible to collect a comprehensive view of how program inputs relate to some property. This can be done using the framework of an alternating conditional analysis (AcA). In this paper, we present a toolset that instantiates an AcA to analyze c programs. The toolset, dubbed ALPAcA (A Large Portfolio-based AcA), computes a sound characterization of all the ways a program either may or must satisfy some property. It does so by alternating between over- and underapproximate analyses, conditioning analyses to ignore portions of the program that have already been analyzed, and combining the results of 14 state-of-the-art analysis tools in a portfolio run in parallel.

关键词： approximation theory c language program diagnostics program verification software tools analysis programme program verification c language Approximation Theory Software Tools Vicugna pacos

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conditional compilation is Dead, Long Live conditional compilation! 41

Conditional Compilation is Dead, Long Live Conditional Compi...

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41st IEEE/AcM International conference on Software Engineering - New Ideas and Emerging Results (IcSE-NIER)

作者： Gazzillo, Paul Wei, Shiyi Univ Cent Florida Orlando FL 32816 USA Univ Texas Dallas Richardson TX 75083 USA

ISBN: (纸本)9781728117584

Highly-configurable systems written in c form our most critical computing infrastructure. The preprocessor is integral to c, because conditional compilation enables such systems to produce efficient object code. However, the preprocessor makes code harder to reason about for both humans and tools. Previous approaches to this challenge developed new program analyses for unpreprocessed source code or developed new languages and constructs to replace the preprocessor. But having specialpurpose analyses means maintaining a new toolchain, while new languages face adoption challenges and do not help with existing software. We propose the best of worlds: eliminate the preprocessor but preserve its benefits. Our design replaces pre-processor usage with c itself, augmented with syntax-preserving, backwards-compatible dependent types. We discuss automated conditional compilation to replicate preprocessor performance. Our approach opens new directions for research into new compiler optimizations, dependent types for configurable software, and automated translation away from preprocessor use.

关键词： conditional compilation preprocessor c language variability dependent types

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contrast study and parameter modification of two mathematical models of human thermal regulation

Contrast study and parameter modification of two mathematica...

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cSAA/IET International conference on Aircraft Utility Systems (AUS 2020)

作者： M. Ke W. chen K. Song J. Zhao Ministry of Industry and Information Technology Nanjing University of Aeronautics & Astronautics Key Laboratory of Aircraft Environment Control and Life Support P.R. China

In order to predict the core temperature of human body in the cockpit, Gagge 2 node model and Tanabe 65 node model are introduced in this paper. The core temperature prediction program of human body was compiled by Using c language, and the comparison found that Tanabe 65 node model and the program prediction accuracy were higher, and the change of core temperature of human body could be effectively predicted. The corresponding parameters of the 65 node model were modified according to the geometric parameters of chinese people. UDF(User Defined Function) was used to embed the 65-node model into the cockpit human body for numerical simulation, which was applied to the heating condition..

关键词： biothermics numerical analysis humidity temperature measurement c language physiology medical computing heating

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PROVIT-cI: A classroom-Oriented Educational Program Visualization Tool

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IEIcE TRANSAcTIONS ON INFORMATION AND SYSTEMS 2018年第2期E101D卷 447-454页

作者： Yan, Yu Hara, Kohei Kazuma, Takenobu Hisada, Yasuhiro He, Aiguo Univ Aizu Grad Dept Comp & Informat Syst Aizu Wakamatsu Fukushima 9650006 Japan Univ Aizu Aizu Wakamatsu Fukushima 9650006 Japan Univ Aizu Div Informat Syst Aizu Wakamatsu Fukushima 9650006 Japan Univ Aizu Comp Sci Aizu Wakamatsu Fukushima 9650006 Japan Maple Syst Co Ltd Tokyo 1040061 Japan

Studies have shown that program visualization(PV) is effective for student programming exercise or self-study support. However, very few instructors actively use PV tools for programming lectures. This article discussed the impediments the instructors meet during combining PV tools into lecture classrooms and proposed a c programming classroom instruction support tool based on program visualization - PROVIT-cI (PROgram VIsualization Tool for classroom Instruction). PROVIT-cI has been consecutively and actively used by the instructors in author's university to enhance their lectures since 2015. The evaluation of application results in an introductory c programming course shows that PROVIT-cI is effective and helpful for instructors classroom use.

关键词： program visualization(PV) educational PV tool introductory programming education c language classroom instruction

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Scheme for variable-frequency digital circuit with data compression based on block-match process

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IET cIRcUITS DEVIcES & SYSTEMS 2018年第3期12卷 295-300页

作者： Jin, Rencheng Zhao, Jipeng Ma, Yuan Zhou, Feng Dalian Univ Technol Res Ctr Microsyst Technol Dalian 116024 Peoples R China

In order to find a way to solve the contradiction among storage space, transmission capacity and the data volume in the embedded systems, a data compression scheme based on block matching with an identifier is presented by using the technology of digital integrated circuit. The scheme can achieve lossless real-time data compression and reduce the volume of the data. Through statistical analysis on the data source, the authors can obtain that such a scheme has many advantages in real-time performance, a complication of implement, efficiency and practicability. So the digital circuit is considered as a method which can present the encoding process. With the help of QUARTUS II, they combine Verilog and schematic to finish the design hierarchically and code the decompression program by using c language for comparison. The accuracy and efficiency of the circuit are verified with simulation and relevant experiments. The average compression rate is 52.3% with 12MHz clock frequency and the compression speed on average is 352% faster than the one by using block-match software algorithm. The scheme would have good performance in many embedded systems.

关键词： digital circuits Scheme Digital integrated circuits Data compression Embedded systems c language block matching Data sources

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The Design of Activity Record in c language compile Process

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2nd International conference on Mechatronics and control Engineering (IcMcE 2013)

作者： Song, Zhichao North China Elect Power Univ Sch Control & Comp Engn Beijing 102206 Peoples R China

ISBN: (纸本)9783037858943

Activity record is an important part of the compile process. c-based storage management strategy, the system uses the Eclipse integrated environment in Windows 7 system, using the Java language to implement process activity record analysis and processing of the c language. Program can handle variables stored procedure calls and nested execution jumps, and through vector symbol table to achieve compact build management. By applying stack storage management strategies,the storage activity can be clearly demonstrated.

关键词： Activity record c language compile theory compile process

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Fast Physics on the Web Using c plus plus , JavaScript, and Emscripten

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cOMPUTING IN ScIENcE & ENGINEERING 2018年第1期20卷 11-19页

作者： Zakai, Alon Mozilla Toronto ON Canada

The web is now capable of running computationally intensive code at near-native speed, enabling new types of content such as physics simulations to be easily shared online. In this article, the author shows how to do just that by writing code in c++ and compiling it to the web with the open-source Emscripten tool, which generates ***, a fast subset of JavaScript that runs in all web browsers.

关键词： c language Java Physics computing Emscripten Java Script c language Web Fast Physics Browsers c languages Physics computational Modeling Benchmark Testing compilers The Rise Of Java Script Web Browsers Programming languages Software Engineering Scripting languages

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