Hiroshi Hosobe

Interactive high-dimensional visualization of social graphs

The paper tackles the problems of the “giant hairballs”, the dense and tangled structures often resulting from visualization of large social graphs. Proposed is a high-dimensional rotation technique called AGI3D, combined with an ability to filter elements based on social centrality values. AGI3D is targeted for a high-dimensional embedding of a social graph and its projection onto 3D space. It allows the user to rotate the social graph layout in the high-dimensional space by mouse dragging of a vertex. Its high-dimensional rotation effects give the user an illusion that he/she is destructively reshaping the social graph layout but in reality, it assists the user to find a preferred positioning and direction in the high-dimensional space to look at the internal structure of the social graph layout, keeping it unmodified. A prototype implementation of the proposal called Social Viewpoint Finder is tested with about 70 social graphs and this paper reports four of the analysis results.

Autonomous Control of Mobile Robots Using Logical Representation of Map and Inference of Location

We propose an action-decision method for autonomous mobile robots, in which a robot constructs a logical representation of a map of its surrounding environment from its perception and uses that map to determine a plan to logically reach its destination. We conducted an experiment in which a robot had a sub-goal to reach halfway to its destination and attempt to recognize that it has reached that sub-goal in order to proceed to the next goal. We first explain our experimental results then provide a discussion on these results and future work.

Hardened Flow-Sensitive Trace Formula for Fault Localization

In formula-based fault localization methods, a program under test, which is unrolled to a certain bound, is encoded in a trace formula (TF). The efficiency and precision of the fault localization algorithm depend highly on the way this formula is encoded. The full flow-sensitive TF can cover all potential root causes, but is usually large and scalability problems remain. We propose a new encoding, the hardened flow-sensitive trace formula (HFTF), which reduces the complexity of the formula but does not lose essential control flow graph (CFG) information required for localizing faults. The HFTF is constructed using a concolic execution method that generates both failing and successful executions and uses the coverage information from these executions to simplify the trace formula.

A 2-by-6-Button Japanese Software Keyboard for Tablets.

Increasingly more people are using tablets. When they enter text, they usually use software keyboards. However, such software keyboards are not specialized in tablets. In this paper, we propose a software keyboard for tablets. Tailored to its user’s use of the index, middle, and third fingers on a tablet screen, the keyboard consists of 2-by-6 buttons. It is focused on Japanese kana characters, and enables the user to enter a character usually with two strokes. We present the results of the experiment that we performed to evaluate the proposed keyboard by comparing it with a standard QWERTY software keyboard. The results indicate a trade-off between the average time lengths for entering a character and the average error rates for entering a word; the proposed keyboard resulted in a lower average error rate but in a longer average time length.

A Hand Gesture-Based Method for Biometric Authentication

With the spread of computers to ordinary people, computer security is becoming increasingly important. User authentication is one of the most important technologies for computer security. Although passwords are used in many personal computers, they are known to sometimes have problems. As an alternative to passwords, biometric authentication, such as fingerprint authentication and face recognition-based authentication, is becoming more widely used. In this paper, we propose a hand gesture-based method as a new kind of biometric authentication. It supports three-dimensional (3D) gestures that allow its user to move the user’s hand without touching an input device. Using the motions of fingertips and finger joints as biometric data, the method improves the performance of authentication. Also, we propose seven 3D gestures that can be classified into three types. We implemented the method by using a 3D motion sensor called the Leap Motion controller. We present the results of an experiment that we conducted with nine participants to evaluate the method. For all the gestures, the true acceptance rates were more than 90%, and the equal error rates were less than 4%.

A dynamic default revision mechanism for speculative computation

In this work a default revision mechanism is introduced into speculative computation to manage incomplete information. The default revision is supported by a method for the generation of default constraints based on Bayesian networks. The method enables the generation of an initial set of defaults which is used to produce the most likely scenarios during the computation, represented by active processes. As facts arrive, the Bayesian network is used to derive new defaults. The objective with such a new dynamic mechanism is to keep the active processes coherent with arrived facts. This is achieved by changing the initial set of default constraints during the reasoning process in speculative computation. A practical example in clinical decision support is described.

Biometric Authentication Using the Motion of a Hand

We propose a hand gesture-based spatial interaction method for biometric authentication. It supports 3D gestures that allow the user to move his/her hand without touching an input device. Using the motions of fingertips and joints as biometric data, the method improves the accuracy of authentication. We present the results of experiments, where subjects performed three types of gestures.

A Reasoning Module for Distributed Clinical Decision Support Systems

One of the main challenges in distributed clinical decision support systems is to ensure that the flow of information is kept. The failure of one or more components should not bring down an entire system. Moreover, it should not impair any decision processes that are taking place in a functioning component. This work describes a decision module that is capable of managing states of incomplete information which result from the failure of communication between components or delays in making the information available. The framework is also capable of generating scenarios for situations in which there are information gaps. The proposal is described through an example about colon cancer staging.

Toward a new constraint imperative programming language for interactive graphics

To construct interactive graphics such as graphical user interfaces and interactive webpages is an important matter in computer programming. For this purpose, imperative programming usually has been used. On the other hand, researchers have been attempting to apply constraint programming to interactive graphics. Furthermore, the paradigm of constraint imperative programming has been proposed. This position paper reports our ongoing work on P5CP, a new constraint imperative programming language for interactive graphics. To integrate imperative and constraint programming, we adopt the notion of events in imperative programming and the notion of guards in concurrent constraint programming. We show a simple example program in this language.

A Mouse-Like Hands-Free Gesture Technique for Two-Dimensional Pointing

The use of motion sensing for input devices is becoming increasingly popular. In particular, hands-free gesture input is promising for such devices. We propose a mouse-like hands-free gesture technique for two-dimensional pointing. It is characterized as follows: (1) a user horizontally moves his/her hand to position a cursor shown on a vertical screen; (2) the user activates cursor movement by opening his/her hand, and deactivates it by clenching; (3) the user performs target selection by “clicking” in the air with his/her index finger; (4) the user is assisted in quick but precise cursor movement by automatic acceleration. We present results of a user study that experimentally compared the mouse-like technique with a tablet-like one.