• 한국통신학회논문지
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• 제23권5호
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• pp.1291-1298
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• 1998

In this paper, a simple algorithm for detection of timing error of a synchronous, band-limited, multi-level data stream is proposed. The proposed algorithm can be applied to multi-level PAM, M-ary PSK, or M-ary QAM. The proposed algorithm for M-ary PSK requires only two samples per symbol for its operation, and it is based on the concept of transition logic table and transition level table. In orer to prove the steady-state operation of the proposed algorithm, its performance is evaluated and compared to BECM by Monte Carlo simulation method under Gaussian noise and fading noise channel environments. The comparison results confirm that the perforance of proposed algorithm is superior to that of BECM in jitter characteristics.

• 경영과학
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• 제12권2호
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• pp.43-62
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• 1995

For a complex scheduling system like time table construction, its optimal solution, if exists, is hard to obtain. In this paper, the scheduling environment is reasonably confined as where objects have their own events competing for better slots on boards, and objects have their own board slot preferences and belong to one or more classes of the society which globally constrains them. Here, two phase method is suggested, where the first phase is human-like preference driven and the second phase is for fine tuning by considering all the factors given. Designed and implemented in our system HI-SCHED are dynamic object switching, temporal-constraint-driven intelligent backtracking, case-based revisions, object-based approach, and so on. Some satisfaction degrees are also defined to measure the usefulness of our method. In addition, look-ahead dynamic object switching is considered, and additional global constraints are introduced and processed. A simple scheme is also used to verify the usefulness of the post processing scheme.

• 한국통신학회논문지
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• 제21권3호
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• pp.747-752
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• 1996

In this paper, we propose a new SO-MLSE(soft-output maximum likelihood sequence estimation) equalizer, which can be used in GSM digital cellular system) it uses complex correlation of training sequence to obtain the channel information and the equalization is performed by MLSE using Viterbi algorithm. In order to generate a soft-decision input to channel decoder (Viterbi decoder), the soft-output equalization algorithm is needed. The adopted algorithm doesn't require to modify the structure of HO-MLSE(hard output MLSE) equalizer, that is, SO-MLSE equalizer can be implemented by adding soft-output generation block to HO-MLSE equalizer. This algorithm uses the outputs of matched filter and HO-MLSE equalizer. It turns out that the complexity of proposed SO-MLSE equalizer is simpler than those of other SO-MLSE equalizer and its perforance is almost the same as those of others. Finally, the proposed SO-MLSE equalizer is also implemented s a prototype with ADSP-2101 16-bits fixed point digital signal processing chip.

• 전자공학회논문지S
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• 제34S권2호
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• pp.79-93
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• 1997

This paper presents a linear shift-invariant system euqivalent to morphological dilation for a memoryless uniform source in the sense of the power spectral density function, and comares it with dialtion. This equivalent LSI system is found through spectral decomposition and, for dilation and with windwo size L, it is shown to be a finite impulse response filter composed of L-1 delays, L multipliers and three adders. Th ecoefficients of the equivalent systems are tabulated. The comparisons of dilation and its equivalent LSI system show that probability density functions of the output sequences of the two systems are quite different. In particular, the probability density functon from dilation of an independent and identically distributed uniform source over the unit interval (0, 1) shows heavy probability in around 1, while that from the equivalent LSI system shows probability concentration around themean vlaue and symmetricity about it. This difference is due to the fact that dilation is a non-linear process while the equivalent system is linear and shift-ivariant. In the case that dikation is fabored over LSI filters in subjective perforance tests, one of the factors can be traced to this difference in the probability distribution.

• 한국치위생학회지
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• 제1권1호
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• pp.53-62
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• 2001

The purpose of this study was to measure of dental impact on daily lining among workers. The number of subjects were 1.457 workes. To predict the oral health of workers, we used the measurement of dental impact on daily living. Using methodology was self-questionnaire which included the perceived oral health status, and performance, appearance, pain, eating restriction and discomfort. The associations between the performance factors and perceived oral health status, pain, eating restriction and discomfort, the results were as follows: 1. There were consisted of 48.3% of female. 63.1% of smokers. 92.3% of lower than 30years and 99.4% of graduating high school. 2. Measurement of daily impact on daily living were classified into the following 6 categories. Facter analysis for validity was carried out for corroboration. 3. Association between performance factors and other factors(pain, eating restriction and discomfort) were evaluated by multiple regression was significant(44%, p<0.01).

• 한국통신학회논문지
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• 제21권12호
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• pp.3086-3097
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• 1996

일반적으로 망의 성능은 경로 설정, 대역폭, 각종 타이머등과 같은 다양한 파라메타에 따라 달라진다. 이러한 파라메타의 설정은 망 설계나 운영상에서 시스템의 효율성이나 안정화 관점에서 적절히 선택하여 적용한다. 그러나, 링크나 노드의 장애, 트래픽 폭주 등과 같은 망 환경에 동적으로 적용하기에는 많은 어려움이 야기된다. 이러한 동적인 변화는 망의 제어와 관리를 통하여 망의 파라메타를 변경시킴으로써 망의 성능을 향상 시킬수 있다. 본 연구에서는 이러한 프로토콜 파라메타와 망의 성능 사이에 관계를 이용하여 망의 전반적인 성능 향상을 위한 성능 관리 모델을 제시한다. 본 연구에서는 ATM 망을 대상으로 하였으며, 경로 설정 파라메타와 대역폭 변경 파라메타가 성능에 영향을 미치는 정도를 조사하여 효율적인 성능 관리 모델을 제시한다.

• 복식
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• 제32권
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• pp.243-259
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• 1997

The object of this research is to inform readers of the chronikal change of Military Uniform in wars how the features and colors of uniforms have been changed along with the innovations of firearms. Military uniforms can be put into two differ-ent categories which are 'Battle wear' and 'Rank wear' A battle wear features of protec-tion and user fiendliness, These features of a battle wear can possibly minimize injuries and help increase the level of battling perform-ance. On the other hand a rank wear help dis-tinguish soldiers from their ranks and posi-tions. A rank wear symbolizs the pride that soldiers take n their unit and by wearing a rank wear soldiers feel more attached to their collegues and unit. Concrete process of military uniforms is as follows. 1. As firearms were innovated corres-pondant innovation of military uniforms were also needed this innovation were in the formstructure design color etc. 2. In the beginning features of military uniforms changed toward protection and then after social status of solders rised features changed forward show-off Finally as firearms became more fortal camouflage became the most significant feature of the military uniforms. 3. During war colors of military uniforms tended to be a means of show -off and camou- flage and while not in war they functioned as symbol which represent froops and the unit is tradition. 4. Other accessaries support the perforance and the symbolical function of uniforms.

• 한국통신학회논문지
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• 제21권1호
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• pp.91-102
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• 1996

ATM(asynchronous transfer mode)망에서 멀티미디어 트래픽이 효율적으로 전송되기 위해서는 전송되는 트래픽의 특성이 충분한 고려된 경로설정이 이루어져야 한다. 본 논문에서는 ATM망의 가상경로/가상채널의 특성을 기반으로한 점 대 다중점 경로설정 알고리즘을 제안한다. 제안한 알고리즘은 가상경로 트리를 사용하며 경로설정시 가상경로/가상채널 스위칭의 특성이 반영된 비용함수를 사용하였다. 또한 비용함수는 링크 비용, 지연 및 지연에 대한 가중치로 구성되며 지연에 대한 가중치는 트래픽의 지연감도에 의해 결정된다. 제안한 알고리즘은 트래픽의 지연한계를 만족시킬 수 있는 경로를 설정할 뿐만 아니라, 동일한 경로설정 비용을 가지는 지연한계내의 경로중 지연을 최적화하는 경로를 선택할 수있다. 또한 지연에 대한 가중치를 조절하여 지연 및 비용에 최적화된 알고리즘에 근사한 성능을 가질 수있다. 시뮬레이션 결과, 제안된 알고리즘은 가중치가 0.8에서 1사이에 존재할 때 경로설정 비용측면에서는 비용에 최적화된 알고리즘의 성능에 근사하였으며, 종단간 지연측면에 있어서는 지연이 강하게 반영된 알고리즘의 성능에 근사되었다.

• Journal of Preventive Medicine and Public Health
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• 제30권4호
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• pp.884-892
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• 1997

Currently, there are 100 community emergency centers which expect to provide professional emergency care like Level 1 trauma centers in U.S.A. To evaluate perforance of emergency centers, most studies have been widely adopted death rate based methods such as Trauma and Injury Severity Score(TRISS) and A Severity Characterization of Trauma(ASCOT). However, these methods are only applicable in situation where registration process of trauma patients is well established. Therefore, an alternative method should be applied to evaluate performance of emergency centers in Korea which does not have well-developed registration scheme. This study aims to develop new performance measures which are applicable to Korea and evaluate performance of 35 community emergency centers through new measures. The new measures are included that 'W-statistic' ; death rate calculated on the basis of International Classification based Injury Severity Score(ICISS), and 'the degree of severity' ; rate of severe trauma patients of each emergency medical centers. The study results can be summarized as follows. First, about 34% of sample emergency centers show they provide proper care in terms of their function. Second, tertiary hospitals, university hospitals, and hospitals located in Seoul show higher severity degree of patients and lower severity-adjusted death rate.

• 한국정보처리학회논문지
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• 제5권8호
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• pp.1997-2012
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• 1998

병렬 시스템에서 순차 자바 프로그램을 재 사용할 수 있기 위해서는 자바 프로그램 내에 존재하는 병렬성을 찾아내는 것이 중요하다. 자바 프로그램을 병렬 시스템에서 실행할 경우 루프는 전체 수행 시간 중 많은 부분을 차지하므로 병렬성 검출의 기본이 되지만 데이터 종속으로 인하여 완전한 병렬 수행을 쉽게 이룰 수 없다. 따라서, 본 논문은 기존의 중첩 루프 구조를 갖는 자바 프로그래밍에서 데이터 종속성 분석에 의한 종속 그래프를 구성하여 묵시적 병렬성을 검출하는 방법을 제안한다. 또한 재구성 컴파일러에 의하여 자바 원시 프로그램을 자바 프로그래밍 언어 자체에서 지원하는 다중스레드 기법으로 변환하여 병렬 시스템에서 실행하는 방법을 제안한다. 스레드 문장으로 변환된 프로그램에 대해 루프의 반복계수와 스레드 수를 매개변수로 하여 성능 분석을 하였다. 재구성 컴파일러에 의한 장점은 사용자의 병렬성 검출에 대한 오버해드를 줄이고, 순차 자바 프로그램에 대한 효과적인 병렬성 검출을 가능하게 하여 병렬 시스템에서 실행 시간을 단축할 수 있다.