Michael Siff

BA, BSE., MSE, University of Pennsylvania. PhD, University of Wisconsin-Madison. Special interests in programming languages, cryptology, and software engineering; author of research papers on interplay between type theory and software engineering. SLC, 1999–

Undergraduate Courses 2017-2018

Computer Science

Data Structures and Algorithms

Intermediate , Seminar—Spring

Permission of the instructor is required. Students should have at least one semester of programming experience.

In this course, we will study a variety of data structures and algorithms that are important for the design of sophisticated computer programs, along with techniques for managing program complexity. Throughout the course, we will use Java, a strongly typed, object-oriented programming language. Topics covered will include types and polymorphism, arrays, linked lists, stacks, queues, priority queues, heaps, dictionaries, balanced trees, and graphs, as well as several important algorithms for manipulating these structures. We will also study techniques for analyzing the efficiency of algorithms. The central theme tying all of these topics together is the idea of abstraction and the related notions of information hiding and encapsulation, which we will emphasize throughout the course. Weekly lab sessions will reinforce the concepts covered in class through extensive, hands-on practice at the computer.

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Computer Organization

Intermediate , Seminar—Fall

Permission of the instructor is required. Students should have at least one semester of programming experience.

The focus of this course is on the selection and interconnection of components that make up a computer. There are two essential categories of components in modern computers: the hardware (the physical medium of computation) and the software (the instructions executed by the computer). As technology becomes more complex, the distinction between hardware and software blurs. We will study why this happens, as well as why hardware designers need to be concerned with the way software designers write programs and vice versa. Along the way, we will learn how computers work from higher-level programming languages—such as Java, Python, and C—down to the basic zeroes and ones of machine code. Topics include Boolean logic, circuit design, computer arithmetic, assembly and machine languages, memory hierarchies, and parallel processing. Special attention will be given to the ARM family of instruction—set architectures—now the world's most common general-purpose microprocessors. Time permitting, we will investigate the relationship between energy consumption and the rise of multicore and mobile architectures.

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Introduction to Computer Programming

Open , Lecture—Fall

This lecture presents a rigorous introduction to computer science and the art of computer programming, using the elegant, eminently practical, yet easy-to-learn programming language Python. We will learn the principles of problem solving with a computer while gaining the programming skills necessary for further study in the discipline. We will emphasize the power of abstraction, the theory of algorithms, and the benefits of clearly written, well-structured programs. Fundamental topics include: how computers represent and manipulate numbers, text, and other data (such as images and sound); variables and symbolic abstraction; Boolean logic; conditional, iterative, and recursive computation; functional abstraction ("black boxes"); and standard data structures such as arrays, lists, and dictionaries. We will learn introductory computer graphics and how to process simple user interactions via mouse and keyboard. We will also consider the role of randomness in otherwise deterministic computation, basic sorting and searching algorithms, how programs can communicate across networks, and some principles of game design. Toward the end of the semester, we will investigate somewhat larger programming projects and so will discuss file processing, modules and data abstraction, and object-oriented concepts such as classes, methods, and inheritance. As we proceed, we will debate the relative merits of writing programs from scratch versus leveraging existing libraries of code. Discussion topics will also include the distinction between decidable and tractable problems, the relationship between programming and artificial intellgence, the importance of algorithmic efficiency to computer security, and Moore's Law and its impact on the evolution on programming languages and programming style. Weekly hands-on laboratory sessions will reinforce the programming concepts covered in class.

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Previous Courses

Introduction to Web Programming

Open , Lecture—Spring
This lecture introduces the fundamental principles of computer science via the use of JavaScript to create interactive Web pages. We will focus on the core triumvirate of Web technologies: HTML for content, CSS for layout, and, most importantly for us, JavaScript for interactivity. Examples of the kinds of Web applications that we will build include a virtual art gallery, a password generator and validator, and an old-school arcade-style game. We will learn JavaScript programming from the ground up and demonstrate how it can be used as a general-purpose problem-solving tool. Throughout the course, we will emphasize the power of abstraction and the benefits of clearly written, well-structured code. We will cover variables, conditionals, loops, functions, recursion, arrays, objects, JSON notation, and event handling. We will also discuss how JavaScript communicates with HyperText Markup Language (HTML) via the Document Object Model (DOM) and the relationship of HTML, JavaScript, and Cascading Style Sheets (CSS). Along the way, we will discuss the history of the Web, the challenge of establishing standards, and the evolution of tools and techniques that drive the Web’s success. We will learn about client-server architectures and the differences between client-side and server-side Web programming. We will consider when it makes sense to design from the ground up and when it might be more prudent to make use of existing
libraries and frameworks rather than to reinvent the wheel. We will also discuss the aesthetics of Web design: Why are some pages elegant (even art) when others are loud, awkward to use, or—worse yet—boring. Weekly hands-on laboratory sessions will reinforce the programming concepts covered in the lecture. No prior experience with programming or
Web design is necessary (nor expected nor even desirable).
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First-Year Studies: Digital Disruptions

Open , FYS—Year

From Bitcoin to Uber and Instagram to Snapchat...to massively multiplayer online games and the Internet of Things, digital technology plays an ever more "disruptive" role in society. In this First-Year Studies seminar, we ponder where this phenomenon may be taking us in the immediate and not-so-immediate future and whether there is (or will be) anything we can (or should) do about it. The miniaturization of electronic computers—and the resulting increase in computing power, decrease in short-term cost to harness that power, and ubiquity of computer networks—brings people and places together, making distances formerly thought of as insurmountable ever more trivial. With the advent of gigabit fiber-optic networks, smart phones, and wearable computers, information of all kinds can flow around the world, between people and objects, and back again in an instant. In many ways, the plethora of smaller, cheaper, faster networked devices improves our quality of life. But there is also a dark side to a highly connected society: the more smart phones, the more workaholics; the more text messages exchanged and the easier the access to drones, the less privacy; the greater reach of the Internet, the more piracy, spam, and pornography; the more remote-controlled thermostats, the greater the risk of cyberterrorism. The first half of this seminar will focus on the relationship between digital networks (the Web, social networks, and beyond) to current events—particularly the economy, politics, and the law. We will emphasize the challenge of privacy and security in such an interconnected world. The second half of the course will focus on the cultural impact of digital technology, ranging from video games and science fiction to the rise of artificial intelligence. This is not a technical course, though at times we will discuss some details that lie behind certain crucial technologies; in particular, the Internet and the World Wide Web.

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Related Disciplines

Digital Zeitgeist

Open , Seminar—Fall

From Facebook, Twitter, and YikYak to massively multiplayer online games, to the Internet of Things, and to disruptive technologies ranging from Bitcoin to Uber, computer networks play an ever-increasing role in our daily lives. Where may this phenomenon be taking us in the immediate and not-so-immediate future? Is there (or should there be) anything we can (or should) do about it? The miniaturization of electronic computers and the resulting increase in computing power, decrease in short-term cost to harness that power, and ubiquity of computer networks bring people and places together, making distances formerly thought of as insurmountable ever more trivial. With the advent of gigabit fiber-optic networks, smart phones, and wearable computers, information of all kinds can flow, in an instant, between people and objects around the world and back again. In many ways, the plethora of smaller, cheaper, faster networked devices improves our quality of life; but we will also consider the dark side of a highly connected society: the more smart phones, the more workaholics; the more text messages and e-mails exchanged, the less privacy; the greater reach of the Internet, the more piracy, spam, and pornography. The nature of a course entitled Digital Zeitgeist is to move with the times, and those times move ever more rapidly. So even this description might seem outdated by the time you read it. Never fear, we will steer our discussion to the “bleeding edge,” as necessary. Consider these news stories (to name but a few) that would not have made it into this description were it written only a year earlier: the Gamergate controversy, “Citizen Four” (and its adoration), the Sony hack, the trial and conviction of the Silk Road founder, and the arrival of the Apple Watch. This is not a technical course, although at times we will discuss some details that lie behind certain crucial technologies—in particular, the Internet and the World Wide Web.

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Related Disciplines

Collaborative Software Development

Advanced , Seminar—Spring

Permission of the instructor is required. Students should have studied at least one semester of computer programming. Preference will be given to seniors who apply as a team, in advance, with a concrete proposal.

Donald E. Knuth, one of the world’s most distinguished computer scientists, has said both that “computer programs are fun to write” and “software is hard.” The goal of this course is to give students a taste of what it is like to design and develop real software. The quotes by Knuth illustrate two themes of this course that are not necessarily at odds: The challenge of writing good software should not offset the pleasure derived from writing it. Some of the main topics that we will cover include: the power of abstraction, the separation of design from implementation, version control, the selection of development environments, the creative use of existing software libraries and tools, the benefits of a flexible approach, the role of maintaining good documentation, and, most importantly, how to write software in teams. No place is the adage “there is no substitute for experience” more relevant than in software engineering. With that in mind, this course is intended to be hands-on. Design and development techniques will be taught primarily by designing and developing a semester-long, collaborative software project. Examples of project categories include (but are not limited to) digital games and mobile applications. Specific topics include: design patterns, including Model-View-Controller; separating user-interface particulars from core algorithms; wireframe techniques; alpha vs. beta testing; using distributed, collaborative software versioning tools such as github; the role of abstract data types and precise API specification; code reviews; workshopping; the less heralded but crucially important roles of documentation writers, software testers, and project managers.

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Related Disciplines

First-Year Studies: Privacy vs. Security in a Networked World

Open , FYS

The Internet was developed at the height of the Cold War as a way to maintain a robust communication system in the event of a nuclear attack. It is ironic, then, that the same technology may put us at risk of 21st-century security threats such as electronic surveillance, aggregation and mining of personal information, and cyberterrorism. In this seminar, we contrast doomsday myths popularized by movies such as War Games with more mundane scenarios such as total disruption of electronic commerce. Along the way, we address questions such as: Does modern technology allow people to communicate secretly and anonymously? Can a few individuals disable the entire Internet? Can hackers launch missiles or uncover blueprints for nuclear power plants from remote computers on the other side of the world? We will also investigate other computer security issues, including spam, computer viruses, and identity theft. Meanwhile, with our reliance on cell phones, text messages, and electronic mail, have we unwittingly signed ourselves up to live in an Orwellian society? Or can other technologies keep “1984” at bay? Our goal is to investigate if and how society can strike a balance so as to achieve computer security without substantially curtailing rights to free speech and privacy. Along the way, we will introduce the science of networks and describe the underlying theories that make the Internet at once tremendously successful and so challenging to regulate. Part of the course will be devoted to learning cryptology—the science (and art) of encoding and decoding information to enable private communication. We will conclude with a discussion of how cutting-edge technologies, such as quantum cryptography and quantum computing, may impact the privacy of electronic communications in the near future. We will hold several informal debates on current topics, such as whether Edward Snowden should be viewed as a hero or a traitor, the ethics of Wikileaks and Anonymous, and whether law-enforcement officials should be required to obtain warrants before examining smartphones.

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Compilers: How Computers Execute Their Programs

Intermediate , Seminar—Fall

Permission of the instructor is required. Students should have already taken at least one semester of computer programming (C, C++, or Java) and, preferably, a course in computer architecture.

Compilers are often known as translators—and for good reason: Their job is to take programs written in one language and translate them to another language (usually assembly or machine language) that a computer can execute. It is perhaps the ideal meeting between the theoretical and practical sides of computer science. Modern compiler implementation offers a synthesis of: (1) language theory: how languages (both natural languages and programming languages) can be represented on, and recognized by, a computer; (2) software design and development: how practical software can be developed in a modular way—e.g., how components of one compiler can be connected to components of another compiler to form a new compiler; and (3) computer architecture: understanding how modern computers work. During the semester, we will write a program implementing a nontrivial compiler for a novel programming language (partly of our own design). Topics we will cover along the way include the difference between interpreters and compilers, regular expressions and finite automata, context-free grammars and the Chomsky hierarchy, type checking and type inference, contrasts between syntax and semantics, and graph coloring as applied to register allocation. Conference work will allow students to pursue different aspects of compilers such as compilation of object-oriented languages, automatic garbage collection, compiler optimizations, and applications of compiler technology to natural-language translation.

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