• Journal of the Institute of Convergence Signal Processing
• /
• v.4 no.4
• /
• pp.66-72
• /
• 2003

In the present paper some fundamentals about exceeding the guard interval of an OFDM system is going to discuss and will introduce method to cancel a ISI and ICI effects. In this paper, the performance characteristics of robust OFDM receiving system algorithm that is composed of a channel estimator using recursive least square(RLS) algorithm in time domain and of a ISI and ICI replica and subtracter using the channel coefficients are presented. By computer simulation method, the effect of suppression of ISI and ICI is demonstrated and compared the BER performance with a conventional 1-tap equalized system. Especially the presented scheme improves the BER performance at low SNRs more or so compared with the conventional one-tap equalized receiving configuration.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.10
• /
• pp.1139-1146
• /
• 2004

The effect of triangular tabs attached at the perimeter of jet nozzle on heat transfer enhancement was investigated experimentally. The modified flow structure was visualized using a smoke-wire method. Four different types of jet nozzle having 0, 4, 6 and 8 tabs were tested at jet Reynolds number Re=15,000 to investigate the effect of tabs on the variation of heat transfer rate. The local and average Nusselt numbers are increased with increasing the number of tabs. At nozzle-to-plate distance of L/D=4, the average Nusselt number was increased about 9.9% at Re=15,000 in the impingement region for the case of 8 tabs attachment. As the nozzle-to-plate distance increases, however, the heat transfer enhancement effect of triangular tabs is reduced. For the case of 4 tabs, the heat transfer enhancement is not so distinctive at L/D=8. As the protrusion depth of tabs into the jet flow increases, the heat transfer rate is also enhanced when the nozzle-to-plate distance is smaller than L/D=6.

• Journal of Broadcast Engineering
• /
• v.11 no.3 s.32
• /
• pp.302-310
• /
• 2006

ITU-R B.O. 1130-4 Digital System E adopted for Korean satellite DMB service is a multimedia broadcasting system based on DS-CDM-QPSK technique which broadcasts audio and video contents via the satellite or terrestrial gap-filler. However, Digital System E can not provide full loading services because the multi-channel interference (MCI) is increased due to the loss of orthogonality between signature waveforms in multipath fading channels. In this paper a chip equalizer using tap selection algorithm that enhances the receiving performance is proposed and compared to the conventional rake receiver for the satellite DMB system.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.11a
• /
• pp.1764-1766
• /
• 2012

현재 스마트폰의 급격한 대중화가 이루어짐에 따라, 터치스크린에서 한글을 효율적으로 입력하는 방법의 연구가 활발히 진행되고 있다. 하지만, 많은 터치스크린 한글 키패드가 만들어졌음에도 불구하고, 사용자가 습득하는데 시간이 오래 걸리며 오타가 빈번하게 나타나고 있다. 따라서 본 논문에서는 한글 키패드의 표준인 '천지인'의 장점인 사용자 습득율을 최대화하고, 단점인 자음의 멀티탭(반복누름)방식으로 인한 오타발생 빈도율을 스마트폰의 터치 슬라이드방식을 이용하여 최소화한 SC-Keyboard를 제안하고자 한다.

• Journal of Korea Multimedia Society
• /
• v.2 no.1
• /
• pp.30-37
• /
• 1999

A wideband active noise cancelling system involves adaptive filters with hundreds of taps. The computational burden required with these long adaptive filters. This paper presents active noise cancelling system using M-channel QMF filter banks in which the adaptive weights are computed in subbands. The analysis and synthesis filter banks use cosine-modulated pseudo QMF filters. The reference signal for on-line identification of error path transfer characteristics is used to difference signal between the output of adaptive filters and the output of lowpass subband filters. The proposed adaptive subband filter bank suggests robust active noise cancelling system retaining the computational complexity and convergence speed advantaged of subband processing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.05a
• /
• pp.240-243
• /
• 2001

As electronic industry and radio communication technologies progress, mankind enjoys its abundant life. On the other hand, it becomes possible that the electrical and electronic equipments are on light weight, small size, high speed, broad bandwidth, and operation by small energy. At the same time, many social problems like EMI/EMS by electromagnetic waves occur. Therefore, tile organizations such as CISPR, FCC, ANCI, etc., have provided the standards of electromagnetic wave environments for the countermeasure of the EMC. In this paper, we designed and studied a new EMI filter for multi-tap in the frequency band from 150 kHz to 30 MHz.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2016.10a
• /
• pp.845-848
• /
• 2016

본 연구는 고층으로 이루어진 카페 고객의 전기 남용 문제를 해결하는 것을 목적으로 한다. 현재 각 카페는 콘센트를 고객에게 제공함으로써 고객의 편의를 돕고 있다. 하지만 고객이 이를 악용하여 장시간 전기를 이용하여 카페 회전율을 낮추고, 이에 따른 전기요금 과다 현상이 나타나고 있다. 따라서 본 연구는 이러한 문제점을 해결하기 위해 카페의 각 콘센트에 멀티 랩을 고정하고 소켓을 PC 응용 프로그램을 통하여 제어하고자 한다. 본 연구를 수행함으로써 장시간 전기를 이용하는 고객과 무단으로 침입하여 전기를 사용하는 고객을 배제 할 수 있다. 또한 전기 사용 기본 제공시간을 정하여 직원의 번거로움을 줄일 수 있다.

• Journal of the Korea Computer Graphics Society
• /
• v.19 no.1
• /
• pp.11-20
• /
• 2013

This paper introduces a user interface for large 3D meshes in mobile systems, which have limited memory, screen size and battery power. A large 3D mesh is divided into partitions and simplified in multi-resolutions so a large file is transformed into a number of small data files and saved in a PC server. Only selected small files specified by the user are hierarchically transmitted to the mobile system for 3D browsing and rendering. A 3D preview in a pop-up shows a simplified mesh in the lowest resolution. The next step displays simplified meshes whose resolutions are automatically controlled by the user interactions. The last step is to render a set of detailed original partitions in a selected range. As a result, while minimizing using mobile system resources, our interface enables us to browse and display 3D meshes in mobile systems through real-time interactions. A mobile 3D viewer and a 3D app are also presented to show the utility of the proposed user interface.

• Proceedings of the IEEK Conference
• /
• 2001.09a
• /
• pp.861-864
• /
• 2001

많은 멀티미디어와 DSP 응용에서 입력과 출력 데이터 길이가 같은 고정 길이 곱셈기가 요구된다. 고정 길이 곱셈기는 확률적인 추정에 근거한 적절한 보상 바이어스를 더해줌으로써 일반적인 병렬 곱셈기와 비교하여 50%의 면적을 줄일 수 있다. 본 논문에서는 CSD 곱셈기에 적합한 고정길이 곱셈기의 구조를 제시하고 전파 캐리 선택절차를 이용한 부호확장제거방법과 결합함으로서 새로운 곱셈기구현 방안을 제시한다. 이 곱셈기의 응용으로서 SSB/BPSK-DS/CDMA 전송방식에 사용되는 힐버트 트랜스포머를 43탭 FIR 필터로 구현하고 기존의 compensation 벡터 방법과 비교하여 약 34%의 부호확장 오버헤드를 줄일 수 있음을 보인다.

• The KIPS Transactions:PartB
• /
• v.14B no.5
• /
• pp.391-400
• /
• 2007

An interactive Hangul input method using the numeric phone keypad, which is applicable for mobile devices is introduced. In the proposed method, user only selects the corresponding keys by single tapping, for the alphabet of Korean letter which is desired to enter. The interface generates the subset of eligible letters for the key sequence, then the user selects the desired letter in the set. Such an interactive approach transforms the text entry interface into a multi-level interactive letter-oriented style, from the preexisting passive and single-level alphabet-oriented interface. The annoyance of key-operations, the major disadvantage of the previous methods, derived from multi-tap to clear the ambiguity of multi-assigned alphabets for the Hangul automata, can be eliminated permanently, while the additional letter selection procedure to finalize the desired letter is essential. Also the complexity of Hangul text entry is reduced since all letters can be compounded from basic alphabet selection of the writing sequence order. The advantage and disadvantage of the proposed method are analyzed through comparing with pre-existing method by experiments.