Yoshikazu Yamamoto

A statistical package based on Pnuts

We are developing a statistical system named Jasp in order to utilize recent advanced computational environments. We design Jasp language based on Pnuts, a script language written in and for Java language. Pnuts is a functional language without type declaration, and is easy to use for tentative and experimental work. We add tools for statistical analysis, and object oriented syntax mainly to bundle related functions. Besides a Jasp language window, Jasp user interface also has a graphical user interface window to show the history of analysis and to operate the system by pop-up menus. These two windows are tightly connected and can be used alternatively. Jasp is realized by client/server approach, and one client can execute calculations on more than one servers and can perform distributed computing. Jasp is able to use programs written in foreign languages such as C, C++ and Fortran.

Using mathematical expressions in a statistical language

Statistical models consist of mathematical expressions and algorithms. In a statistical system, such models are described in a statistical language. Therefore, a statistical language is useful if it can handle mathematical equations directly and connect them with algorithms seamlessly. This ability enables users to write and read programs intuitively and easily. The statistical language having this ability has been implemented in a statistical system Jasp using Java and MathML technologies.

Adding visualization functions of DAVIS to Jasp: Mixing two Java-based statistical systems

SummaryJasp is an experimental general purpose Java-based statistical system which adopts several new computing technologies. It has a function-based and object-oriented language, an advanced user interface, flexible extensibility and a server/client architecture with distributed computing abilities. DAVIS is, on the other hand, a stand-alone Java-based system, and is designed for providing advanced data visualization functions with easy operations by a GUI. In this paper, it is made possible to use tools of DAVIS from within Jasp, in order that the new integrated system can handle not only data filtering and statistical analysis but also data visualization. We develop a mechanism for extending the server/client system of Jasp to realize an efficient collaboration with DAVIS in the client-side. It is shown that the mechanism is straightforward and simple.

An object-based graphical user interface for times series analysis

SummaryWe propose a graphical user interface (GUI) of a statistical system largely based on direct icon operations. Our GUI adopts an object-oriented approach to represent data, statistics and models as instance objects and to depict them as icons on the screen, arranged as a tree to clearly record the history of one data analysis session. When we point at an icon that represents an object we wish to manipulate, a pop-up menu, whose items are statistical procedures available for the object, appears. Selecting an appropriate procedure produces a new object and an icon on the screen to record the process of the analysis. As we can perform all statistical analyses on the tree of icons visually, by following situation-sensitive menus and using simple mouse operations, our GUI is easy to use for many novice users and is useful for preventing the trivial misuse of statistical procedures. We implemented a prototype of the proposed GUI for a time series analysis system named TISAS.

A procedural and object-oriented statistical language

A language of a statistical system is important, even though it bas an effective graphical user interface. A language may be used to control the statistical system at will and to implement new statistical procedures which are not realized in the system at the beginning. This paper introduces the features and the syntax of the language of the statistical system Jasp (Java based statistical processor). We use a procedural function-based script 1anguage Puuts as the basis of the language, and add object-oriented mechanism thinking much of ease, flexibility and extendibility.

A time series analysis system using visual operations

We design and implement a prototype time series analysis system named TISAS for fully using modern graphical user interface technologies. An object oriented approach is adopted to represent data, statistics and models as instance objects and to visualize them by icons on the screen arranged as a tree for recording the analysis process clearly. When we point an icon which represents an object we want to handle, a pop-up menu, whose items are statistical procedures available for the object, appears. The operation that we select an appropriate procedure from the menu, produces a new object as a result and an icon on the screen to record the history of the analysis. As we can perform almost all statistical analysis on a tree of icons visually and directly following situation sensitive menus by simple mouse operations, GUI of TISAS is easy to use for many users, and is useful for preventing trivial misuse.

Programming Statistical Data Visualization in the Java Language

When we have to write programs for statistical data visualization using a generalpurpose programming language, for example, to achieve new functions or extensibility, the Java language is an appropriate choice. The object-oriented characteristics of Java are suitable for building graphical and interactive programs. Java has well-prepared standard graphical libraries that reduce our programming tasks and increase the portability of software to different platforms. Furthermore, recently developed solutions for object-oriented programming – so called “design patterns” – are useful for building statistical data visualization programs.

Representing Knowledge in the Statistical System Jasp

We describe a framework to assist processes of analyzing data in our statistical system Jasp. Recent statistical systems provide so many statistical methods that most users have difficulties to master how to use them properly. In addition, users are sometimes in danger of swallowing results from systems without thinking deeply. In order to prevent these problems, we have implemented rules of “condition - action” forms in Jasp classes to express heuristic knowledge for statistical analysis. By using these rules, Jasp can give advice to users about possible statistical analysis procedures and notify problems when they appear. This ability is useful for users, especially for students and novices in statistics or the Jasp system.

Dynamically-variable adaptive algorithms

Variations of the statistical properties of system inputs may cause a fall of adaptation abilities of the adaptive algorithms. To overcome this problem, we propose a dynamically-changing method of the form of the adaptive algorithms among Kalman filter based, normalized least mean square and recursive least squares methods. The validity of our method was confirmed in the numerical experiments.

Distributed computing in a time series analysis system

In this paper, we consider simple and easy distributed computing abilities of the statistical system TISAS (TIme Series Analysis Supporting System). TISAS was mainly written in the Tcl / Tk language, and was designed for utilizing full merits of a GUI (Graphical User Interface). We add functions for distributed computing without chaIlenging the style of the TISAS GUI by using TkPVM, which is an implementation of PVM (Parallel Virtual Machine) libraries through Tcl / Tk. We adopt a server client system structure for the new version of TISAS. The server part executes data manipulations and the client part does GUI works. For designing them, we use a Model~ View~Controller framework, which makes our implementation relatively simple.