Garbage collection alternatives for icon

Copying garbage collectors are becoming the collectors of choice for very high-level languages and for functional and object-oriented languages. Copying collectors are particularly efficient for large storage regions because their execution time is proportional only to the amount of accessible data, and they identify and compact this data in one pass. In contrast, mark-and-sweep collectors execute in time proportional to the memory size and compacting collectors require another pass to compact accessible data. The performance of existing systems with old compacting mark-and-sweep collectors might be improved by replacing their collectors with copying collectors. This paper explores this possibility by describing the results of replacing the compacting mark-and-sweep collector in the Icon programming language with four alternative collectors, three of which are copying collectors. Copying collectors do indeed run faster than the original collector, but at a significant cost in space. An improved variant of the compacting mark-and-sweep collector ran even faster and used little additional space.     

High-level goal-directed concurrent processing in icon

Concurrent language features have been added to an experimental dialect of Icon called Conicon. These new language features allow Icon to deal with new application domains such as intelligent robot control and real-time natural language processing. Besides widening the scope of Icon's intended application domain, these experimental concurrent processing notations also encourage programmers to revise existing programs to take advantage of the new language capabilities. For example, concurrent evaluation of the alternative arms of compound goal-directed expressions is now possible. This paper describes these concurrent processing notations and presents several examples of their expressive power.     

Everything is alive

The pervasive computing vision is a paradigm shift "back to the future." It could create a world 25 years hence where, once again, everything is alive (EiA) and can sense, act, think, feel, communicate, and maybe even move and reproduce. This might include equipment, vehicles, robots, clothing, pets, and objects such as trees and walls. The assumption behind this paradigm shift is that sensors, actuators, intelligent controllers, software, and communication devices will be virtually free and vanishingly small. They will be able to attach to their hosts transparently and intercommunicate and cooperate to help us with our tasks. This will extend the desktop metaphor so that computing is no longer just inside computers but rather inside all sorts of physical things. Wireless will replace telepathic communication - everything will be Internet-enabled and stamped with "agents inside.".     

Mona Lisa alive

This paper presents a novel approach for creating self-moving objects using hollow-face illusion. Given a clip of character animation, our approach generates a static object. Looking at the object at different views, a similar deformation can be observed. To accomplish this challenging mission, we give qualitative and quantitative analysis of hollow-face illusion. Methodology in computer vision and human perception are utilized to design the algorithm. A static object is first generated to satisfy the relative motion illusion constraints. The illusion is then strengthened by back projecting the object to the 3D face space. Considering both “bottom-up” visual signal and “top-down” knowledge, the intended illusion can be generated. Experiments have shown the effectiveness of our algorithm. For example, expression varying illusion on an oil painting can be created by our method. The self-moving objects can be used in applications such as design, entertainment, advertisement, and public safety.     

A framework for execution monitoring in icon

Execution monitors are widely used during software development for tasks that require an understanding of program behavior, such as debugging and profiling. The Icon programming language has been enhanced with a framework that supports execution monitoring. Under the enhanced translator and interpreter, neither source modification nor any special compiler command-line option is required in order to monitor an Icon program. Execution monitors are written in the source language, instead of the implementation language. Performance, portability, and detailed access to the monitored program's state are achieved using a coroutine model and dynamic loading rather than the separate-process model employed by many conventional monitoring systems.     

Design and evaluation of an adaptive icon toolbar

As information systems become increasingly important in many different domains, the potential to adapt them to individual users and their needs also becomes more important. Adaptive user interfaces offer many possible ways to adjust displays and improve procedures for a user's individual patterns of work. This paper describes an attempt to design an adaptive user interface in a computer environment familiar to many users. According to one classification of adaptive user interfaces, the adaptive bar described in this paper would be classified as a user-controlled self-adaptation system.At the user's convenience, the adaptive bar offers suggestions for adding or removing command icons, based on the frequency and probability of specific commands. It also implements these changes once the user has agreed to them. Beyond the adaptive bar, the general behavior of the whole user interface does not change, thereby allowing the user to maintain a clear general model of the system. This paper describes the decision-making algorithm implemented in the bar. It also describes the bar's self-adaptive behavior of displaying the frequency of each icon's use through the icon's size. Finally, we present some encouraging preliminary results of evaluations by users.     

An optimizing compiler for the icon programming language

Compiling code for the Icon programming language presents several challenges, particularly in dealing with types and goal-directed expression evaluation. In order to produce optimized code, it is necessary for the compiler to know much more about operations than is necessary for the compilation of most programming languages. This paper describes the organization of the Icon compiler and the way it acquires and maintains information about operations. The Icon compiler generates C code, which makes it portable to a wide variety of platforms and also allows the use of existing C compilers for performing routine optimizations on the final code. A specially designed implementation language, which is a superset of C, is used for writing Icon's run-time system. This language allows the inclusion of information about the abstract semantics of Icon operations and their type-checking and conversion requirements. A translator converts code written in the run-time language to C code to provide an object library for linking with the code produced by the Icon compiler. The translation process also automatically produces a database that contains the information the Icon compiler needs to generate and optimize code. This approach allows easy extension of Icon's computational repertoire, alternate computational extensions, and cross compilation.     

Logicon: An integration of prolog into icon

This paper describes the coupling of logic programming with Icon, which is a programming language aimed at string processing. Icon and Prolog have many similarities and their integration is feasible and desirable because the weaknesses of one can be compensated for by the strengths of the other. In our case, a Prolog interpreter was written as an Icon procedure that can be linked and called by an Icon program. This interpreter deals with all Icon data types and can be called in the context of the goal-directed evaluation of Icon. We give an example showing the power of this symbiosis between these two languages where a Prolog call in Icon is a generator and an Icon call in a Prolog clause is a built-in predicate.     

The implementation of generators and goal-directed evaluation in icon

Two features of the Icon programming language strongly influence its implementation: generators and goal-directed evaluation. A generator is an expression that is capable of producing a sequence of results. In goal-directed evaluation, the results of generators are produced automatically in an attempt to complete computations successfully. This paper describes the generated code and run-time support for generators, goal-directed evaluation, and related control structures.     

A portable storage management system for the icon programming language

Icon is a new programming language designed primarily for non-numerical applications. Its roots are in SNOBOL4 and SL5; as in those languages, execution-time flexibility is an important attribute of Icon, although some aspects of programs are bound at compile time to improve efficiency. Icon, which is implemented in Ratfor, is also intended to be portable and suitable for 16-bit computers. The storage management system in Icon is designed to meet the goals of portability, flexibility and efficiency. This is accomplished by subdividing the storage management system into a set of type-specific storage management subsystems. This paper describes the implementation of these subsystems, their interaction, and their performance.     

在多媒体Authorware软件中如何控制电影图标

电影的创作需要精湛的技术和创新性的思想作为基础,声音和动画更是其制作过程中不可缺少的重要组成部分。或悠扬或动感的音乐、或旋转或跳跃的动画的加入让影视作品更加充实完满,带给观看者关的享受。为方便影视多媒体的制作与传播,Micromedia公司以流程图标作为基本,研发了一套专门提供声音图标和数字视频图标、在交互式应用程序中仍可加栽多媒体信息,同时对播放使用参数不设置任何控制的交互式媒体编辑制作软件,即Authorware。本文就运用Authorware软件中控制电影图标的功能介绍,探究优秀影视作品制作背后的魅力与奇迹。     

Macular degeneration and visual icon use: deriving guidelines for improved access

The objective of this study was to derive empirical knowledge of the visual search strategies of computer users who suffer from age-related macular degeneration (AMD). This was accomplished by recording eye movement during the use of feature-enhanced software. The results from this study show that there are differences between users who have AMD and users who are fully sighted (FS). Detailed analyses confirmed the hypotheses that there would be performance differences between the AMD and FS participants, and that specific features of the interface, namely icon size, background color, and the number of icons on a display, would significantly affect the search strategies of users. Published online: 29 January 2002     

The design and implementation of dynamic hashing for sets and tables in icon

Two key features in the Icon programming language are tables and sets. An Icon program may use one large set or table, or thousands of small ones. To improve space and time performance for these diverse uses, their hashed data structures were reimplemented to dynamically resize during execution, reducing the minimum space requirement and achieving constant-time access to any element for virtually any size set or table. The implementation is adapted from Per-Åke Larson's dynamic hashing technique by using well-known base-2 arithmetic techniques to decrease the space required for small tables without degrading the performance of large tables. Also presented are techniques to prevent dynamic hashing from interfering with other Icon language features. Performance measurements are included to support the results.     

Icon identification in context: the changing role of icon characteristics with user experience

OBJECTIVE: This research examined the relative importance of icon characteristics in determining the speed and accuracy of icon identification. BACKGROUND: Studies to date have focused on the role of one or two icon characteristics when users first experience an icon set. This means that little is known about the relative importance of icon characteristics or how the role of icon characteristics might change as users gain experience with icons. METHODS: Thirty participants carried out an icon identification task over a long series of trials to simulate learning through experience. Icon characteristics investigated included semantic distance, concreteness, familiarity, and visual complexity. RESULTS: Icon characteristics were major determinants of performance, accounting for up to 69% of the variance observed in performance. However, the importance of icon characteristics changed with experience: Semantic distance is crucial initially while icon-function relationships are learned, but familiarity is important later because it has lasting effects on access to long-term memory representations. CONCLUSION: These findings suggest that icon concreteness may not be of primary importance when identifying icons and that semantic distance and familiarity may be more important. APPLICATION: Designers need to take into account icon characteristics other than concreteness when creating icons, particularly semantic distance and familiarity. The precise importance of the latter characteristics will vary depending on whether icons are rarely encountered or frequently used.