Eun-Jee Song

Wearable assistance system for interacting with electronic devices in smart digital home

In the near future, we will frequently interact with many electronic devices that will be arrayed around us in a smart digital home. Under such circumstances, excessive interactions with these devices may become burdensome. A wearable computer able to understand the context of human activity and communicate autonomously with the surrounding electronic devices might function as an assistant in the daily life of people living in smart homes, thus alleviating that potential burden of excessive manual electronic interactions. In this paper, we present a wearable computer that can interact both with users and with electronic devices. We also propose an Infrared Identification system that can automatically identify the device that a user wants to use. Utilising these interaction capabilities, the proposed wearable computer mediates between the user and surrounding devices while offering a more user-friendly interface.

A Study on the Effective Algorithm by Fourier Transform for Numerical Conformal Mapping

Conformal mapping has been a familiar tool of science and engineering for generations. The methods of numerical mapping are usually classified into those which construct the map from standard domain such as the unit disk onto the ‘problem domain’, and those which construct the map in the reverse direction. We treat numerical conformal mapping from the unit disk onto the Jordan regions as the problem domain in this paper. The traditional standard methods of this type are based on Theodorsen integral equation. Wegmann’s method is well known as a Newton-like efficient one for solving Theodorsen equation. An improved method for convergence by applying low frequency pass filter to the Wegmann’s method was proposed. In this paper we propose an effective algorithm for numerical conformal mapping based on the improved method. This algorithm is able to determine the discrete numbers and initial values automatically in accordance with the given region and the required accuracy. This results come from analyzing the shape of given domain as seen in the Fourier Transform.

Stability of Explicit Symplectic Partitioned Runge-Kutta Methods

A numerical method for solving Hamiltonian equations is said to be symplectic if it preserves the symplectic structure associated with the equations. Various symplectic methods are widely used in many fields of science and technology. A symplectic method preserves an approximate Hamiltonian perturbed from the original Hamiltonian. It theoretically supports the effectiveness of symplectic methods for long-term integration. Although it is also related to long-term integration, numerical stability of symplectic methods have received little attention. In this paper, we consider explicit symplectic methods defined for Hamiltonian equations with Hamiltonians of the special form, and study their numerical stability using the harmonic oscillator as a test equation. We propose a new stability criterion and clarify the stability of some existing methods that are visually based on the criterion. We also derive a new method that is better than the existing methods with respect to a Courant-Friedrichs-Lewy condition for hyperbolic equations; this new method is tested through a numerical experiment with a nonlinear wave equation.

A Study on the System for Customer Feedback Integration Inference in B2C Service Industries

Recently, due to the rapid distribution of the smart phone, real-time SNS such as Twitter and Facebook has been growing exponentially, and the service provider sales are being affected by the customer feedback (comments from blogs, cafes, SNS etc.) as the customer stance has changed from passive to active as the era of social media arrived. However, the current B2C (Business to Customer) service industry lacks both qualitative and quantitative assessments for services provided to customers, causing the same problems to occur repeatedly and periodically. There are relatively low portion of standard process and key performance index because of too many companies and differences of their sizes in these industries. One of the proof of this fact is the need for SSME (Service Science, Management and Engineering) studies in this business area. This paper suggests a method of efficient customer feedback integration for the B2C service industry. The aim of this study is the standardization of process and the development key performance of index, and to develop algorithm about these assessment factors. This method involves collecting and analyzing the customer feedback in various ways (process mining, text mining, direct survey, and face recognition) as well as inferring systematically based on the real-time feedback for satisfaction and personal requirements for providing personalized and customized services. The result of this study is the development of general purpose platform for B2C service process improvement.

A Study on the Methods for Solving the Theodorsen Equation for Numerical Conformal Mapping

Conformal mapping has been a familiar tool of science and engineering for generations. Determination of a conformal map from the unit disk onto the Jordan region is reduced to solving the Theodorsen equation, which is an integral equation for boundary correspondence functions. There are many methods for solving the Theodorsen equation. It is the goal of numerical conformal mapping to find methods that are at once fast, accurate, and reliable. In this paper, we analyze Niethammer’s solution based on successive over-relaxation (SOR) iteration and Wegmann’s solution based on Newton iteration, and compare them to determine which one is more effective. Through several numerical experiments with these two methods, we can see that Niethammer’s method is more effective than Wegmann’s when the degree of the problem is low and Wegmann’s method is more effective than Niethammer’s when the degree of the problem is high.