• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.240-244
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• 2009

In this paper, we present FloatingPad, a touch pad based device with better scrolling feature and more interaction styles than a traditional touch pad. When we interact with a real object like a picture or a book, we manipulate on the object, and we also move, rotate, and flip the object. We applied this idea into a touch pad. In FloatingPad, the touch pad is not fixed to the device. It is floating on the device; it can be slid on the device. Therefore a user can have additional degree of freedom of input by shifting and rotating the touch pad while having the traditional touch pad input. By using this technique, the interactivity of the touch pad can be augmented, and better scrolling feature can be provided by reducing clutching occurs on the position scrolling devices by using the movement of the touch pad as rate control. We implemented the prototype device and conducted a user study with three applications developed for FloatingPad.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1334-1342
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• 1997

The future data communications are expected to support the various andcomplex services withmultimedia. So thispaper has focused on the multimedia synchronization problem which has important position in multimedia presentation. Firstly, this paper consider the suitable layer for multimedia synchronization in the communication structure as transport layer or upper ones, in which we propose synchronization mechanism using fixed length buffer with bufer-lever or upper ones, in which we propose synchronization mechanism using fixed length bufer with buffer-level. The proposed mechansim also supports intra-and inter-media synchronization among media. Through simulation, we prove our analysis of the fixed-length buffersize that theproposed mechanism can provide. Also we show comparisons between our mechanism and other scheme.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06d
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• pp.183-188
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• 2007

Peer-to-Peer (P2P) overlay networks have drawn much research interest in the past few years because they provide a good substrate for large-scale applications in the Internet. In this paper, we introduce the use of anycast, a new "one-to-one-of-many" communication method in the Internet, to solve the following common problems of P2P overlay networks: load-balancing, topology-awareness, system partitioning, and multi-overlay interconnection. We also give an analysis of the features and limitations of the recently deployed anycast infrastructures in the Internet for supporting P2P overlay networks.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.585-588
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• 2007

WMNs(Wireless Mesh Networks)은 기존 유 무선망 구축 시 발생하는 고가의 비용 및 이동성 제약 등의 단점을 극복하기 위해 제안된 네트워크 구조로써 네트워크 구축비용에 비해 광범위한 인터넷 접근영역을 제공하는 장점을 가진다. 특히, IEEE 802.11e를 MAC 계층으로 사용하는 WMN은 기존 IEEE802.11에서 보다 강화된 QoS(Quality of Service)기능을 가지므로, 안정적 멀티미디어 관련 응용 계층을 지원하는 WMN 구축을 위해 주목받고 있는 기술 중 하나이다. 본 논문은 광주과학기술원에 설치된 MIMC(Multi-Interface Multi-Channel) WMN 테스트베드를 QoS 기능 지원을 위해 IEEE 802.11e 기반으로 확장한다. 특히, 확장에 필요한 소프트웨어 요소 및 하드웨어 요소에 대해 논한다. 또한, 확장된 IEEE 802.11e WMN 테스트베드를 사용하여 현재 주목받고 있는 IEEE 802.11e기반 WMN의 기본 쓰루풋 성능, 쓰루풋 차별화 성능등을 실험적으로 분석한다.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2E
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• pp.65-72
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• 1995

An algorithm for evaluating the subjective performance of a loudspeaker is proposed based on the frequency response characteristic. Objective ratings using the proposed algorithm were compared with the results of the listening test. It was verified that the ratings of the proposed algorithm showed a good correspondence with the results of the listening test.

• Smart Media Journal
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• v.1 no.4
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• pp.79-83
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• 2012

In software development process, increasing the size of project(scaling up) is not a same problem as scaling up the parts of small project. Scaling up a project should accompany the communications, and cost, productivity, qualities, development activity, methodologies etc should be considered with it. In this paper, the effective usage of the important elements are discussed in order not to fail to scale up a project.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.405-410
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• 2014

In this paper, we compare the quality of images reconstructed by a conventional delayed-sum (DS) algorithm and radiation pattern-based DS algorithm. In order to evaluate the quality of images, we apply the target-to-clutter ratio (TCR), which is commonly used in synthetic aperture radar (SAR) image assessment. The radiation pattern-based DS algorithm enhances the TCR of the image by focusing the target signals and preventing contamination of the radar scene. We first consider synthetic data obtained through GprMax2D/3D, a finite-difference time-domain (FDTD) forward solver. Experimental data of a 2-GHz bandwidth stepped-frequency signal are collected using a vector network analyzer (VNA) in an anechoic chamber setup. The radiation pattern-based DS algorithm shows a 6.7-dB higher TCR compared to the conventional DS algorithm.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.63-74
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• 2012

Multicast data communication is an efficient communication scheme, especially inmulti-hop ad hoc networks where the media access control (MAC) layer is based on one-hop broadcast from one source to multiple receivers. Compared to unicast, multicast over a wireless channel should be able to deal with varying channel conditions of multiple users and user mobility to provide good quality to all users. IEEE 802.11 does not support reliable multicast owing to its inability to exchange request-to-send/clear-to-send and acknowledgement packets with multiple recipients. Thus, several MAC layer protocols have been proposed to provide reliable multicast. However, additional overhead is introduced, as a result, which degrades the system performance. In this paper, we propose an efficient wireless multicast MAC protocol with small control overhead required for reliable multicast in multi-hop wireless ad hoc networks. We present analytical formulations of the system throughput and delay associated with the overhead.

• Journal of electromagnetic engineering and science
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• v.16 no.2
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• pp.119-125
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• 2016

In this paper, a method for identifying the appropriate position on the ground plane for antennas is proposed based on the current correlation coefficient ($C^3$). This method explains that the mutual coupling between antennas when locating several antennas on the same ground plane is necessary. Given the current distribution on the ground plane induced by each antenna, easily estimating the coupling between antennas is possible. This paper also demonstrates that the proposed method can be used in the design of a multi-input multi-output system. The measured data are in good agreement with the simulation results.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.72-73
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• 2014

최근 통신 분야에서는 새로운 수익을 창출하기 위해 다양한 융합 서비스 개발이 이루어지고 있다. 이와 같은 융합서비스 개발은 통신 망이 갖고 있는 다양한 기능을 API 형태로 개방한 Open API 기술을 기반으로 이루어지고 있으며, API의 특징상 통신망의 프로토콜을 모르더라도 인터넷을 기반으로 다양한 융합 서비스를 쉽고 빠르게 제작할 수 있다. 최근에는 통신 뿐만 아니라, 통신과 방송이 융합된 서비스 개발을 위해 통신 분야의 Open API와, 방송 분야의 Open API를 융합하는 추세를 보이고 있다. 하지만, 국내에서는 이러한 Open API를 체계적으로 지원 해주는 플랫폼이 존재 하지 않기 때문에, 개발자들이 손쉽게 Open API를 사용하기 힘든 실정이다. 따라서 본 논문에서는 방송통신 융합서비스 플랫폼을 구축하기 위한 사전 연구로써, 현재 제공되고 있는 Open API들의 정보들을 공통적으로 정의하기 위해 메타데이터를 이용하여 정의하는 방법을 연구하였다.