• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5C
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• pp.338-343
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• 2005

MIMO(Multiple Input Multiple Output) systems are considered as one of the most promising systems for next generation mobile communication systems which require efficient frequency resource utilization as well as high data rate transmissions. BLAST-STTC is the MIMO system which transmits information from many of STTC encoder groups with two transmit antennas and cancels the interference from other groups in receiver. In this paper we propose a reverse-ordered iterative decoding scheme for BLAST-STTC systems which achieve full diversity gain for all groups and improve the performance of interference cancellation, and compare the error performance of the proposed scheme with general schemes.

• Annual Conference on Human and Language Technology
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• 2015.10a
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• pp.174-177
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• 2015

자가 지식 학습 프레임워크는 자연어 텍스트에서 지식 트리플을 생성하기 위한 방법 중 하나로, 문장의 의존 관계 트리 상에서 주어 개체와 목적어 개체 사이의 관계를 패턴으로 학습해 이 패턴을 바탕으로 새로운 지식 트리플을 생성한다. 그러나 이 방법은 의존 관계 트리를 생성하는 도구의 성능에 영향을 받을 뿐만 아니라 생성된 지식 트리플을 반복적으로 사용하는 자가 지식 학습의 특성상 오류가 누적될 가능성이 있다. 이러한 문제점을 해결하기 위해서 본 논문에서는 자가 지식 학습 프레임워크에서 생성된 지식 트리플을 TransR 신뢰도 함수를 사용해 신뢰도 값을 측정하여 그 값에 따라 지식 트리플을 필터링하는 방법을 제안한다. 실험 결과에 따르면 필터링 된 지식 트리플들이 그렇지 않은 지식 트리플들에 비하여 더 높은 정확률을 보여주어, 제안한 방법이 자가 지식 학습 프레임워크의 정확률 향상에 효과적임을 증명하였다.

• Journal of Broadcast Engineering
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• v.12 no.6
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• pp.641-648
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• 2007

The decoding structure of up-to-date ATSC DTV receivers is well optimized, and it seems that 14.6 dB is the unbreakable minimum SNR in the AWGN channel. But the SNR satisfying the Shannon capacity of DTV receivers is 11.76 dB, So, the SNR gab between the 14.6 dB and the 11.76 dB is about 2.8 dB. In order to approach the Shannon capacity we propose a recursive trellis decoder which uses reliable feedback data obtained by an RS decoder. The performance enhancement of about 0.8 dB can be achieved in case of the AWGN channel.

• The Korean Journal of Applied Statistics
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• v.28 no.2
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• pp.221-230
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• 2015

Traditionally, sib-pair linkage analysis with repeated measures has employed linear mixed models, but it suffers from the lack of power to find genetic marker loci associated with a phenotype of interest. In this paper, we use a gamma mixed model to improve sib-pair linkage analysis and compare it with a linear mixed model in terms of power and Type I error. We illustrate that the use of gamma mixed model can achieve higher power than linear mixed model with Genetic Analysis Workshop 13 data.

• Proceedings of the Korean Statistical Society Conference
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• 2005.05a
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• pp.291-298
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• 2005

지속성 외래 복막투석은 말기 신부전 환자들에게 널리 시행하는 신 대체 요법으로, 복막투석 환자에게서 주된 합병증으로 일어나는 단백질-열량 영양실조를 치료하기 위하여 아미노산을 복강 내로 주입하는 치료방법이다. 이현석 등(2004)의 연구에서는 아미노산 복막 투석액(IPAA)이 영양실조 환자들에게 실제로 영양상태에 미치는 영향을 평가하기 위하여 지속성 외래 복막투석 환자 43명을 12개월 동안 3개월 주기로 관측하여 얻어낸 반복측정자료를 바탕으로 IPAA의 효과 여부에 따라 반응군과 비반응군을 분류하였다. 본 논문에서는 이러한 두 그룹을 효과적으로 분류할 수 있는 분류기준변수들을 찾아내고 이 분류기준변수의 값을 바탕으로 새로운 환자에게 IPAA의 투여 여부를 진단할 수 있는 여러 분류방법들을 고찰하여 비교 연구하였다. 모수적인 방법으로 선형판별분석, 이차판별분석 및 로지스틱 판별분석을 소개하고 비모수적인 방법으로 support vector machine(SVM)을 소개하여 분류분석의 결과를 비교하여 두 그룹을 최소한의 오류로 분류하는 방법을 제안하였다.

• Archives of design research
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• v.19 no.4 s.66
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• pp.101-110
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• 2006

In this study, I suggested a new model of universal web navigation design which can enhance users' web usability. I would like to prove that when users enjoy web navigation design, they access information much more effectively. Using a survey, I suggest some types of web navigation design for users. After that, I conducted an experiment with 4 types of web navigation designs, which have been developed to reflect varying stages of comprehensibility. My survey focused on three points. First I measured the time they spent to search for information. Second, I tested whether they lost their way while searching for information and if they did lose their way, I checked whether they could recover from their errors and find their way back. Third, I investigated whether layout, location and size of the web navigation design factors affected usability. The results of my survey indicated that users spend the shortest time, have the easiest interface, and have least error incidence under the web navigation design to enhance old-aged users' web usability. Thus, developing a universal web navigation design can encourage people to be more involved with the internet.

• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.124-137
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• 2024

Malrotation and midgut volvulus are surgical emergencies that commonly occur within the first month of life. The classic symptom is acute bilious vomiting, while nonspecific symptoms such as recurrent abdominal pain may be present in older children. Malrotation can be associated with duodenal obstruction caused by an abnormal peritoneal fibrous band or congenital anomalies, such as an annular pancreas or a preduodenal portal vein. Volvulus can lead to bowel ischemia and a life-threatening condition, thus prompt and accurate diagnosis is crucial. Diagnosis can be made through upper gastrointestinal series, ultrasonography, and CT, with ultrasonography being preferred as a screening tool due to its rapid and accurate diagnosis, without radiation exposure, in children. This pictorial essay discusses the key imaging findings and diagnostic approaches for malrotation and midgut volvulus, as well as diagnostic pitfalls based on actual cases.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.187-195
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• 2018

In this study, using real-time gaze tracking and head tracking method, we intended to quantitatively evaluate the deviation between the patient's head and gaze direction while minimizing inspection errors due to apraxia of conventional paper-based examination respectively. As a result, we developed a software that can quantitatively measure gaze and head movement information, and computerized the line bisection and star cancelation test, which are generally used as conventional paper test. In addition, for the rehabilitation training, contents corresponding to the visual technology of Warren's visual hierarchical model lower level are implemented and can be performed repetitively and independently. This allows the patient to actively participate in rehabilitation and quantitatively compare the degree of improvement.

• Journal of Advanced Navigation Technology
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• v.16 no.6
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• pp.988-996
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• 2012

Assuming perfect channel state information (CSI), the conventional interference alignment (IA) algorithm in the uplink cellular system suppresses inter-cell interference (ICI) by aligning ICI to a randomly selected reference vector. However, IA in practice relies on limited feedback between base stations and users, resulting in residual ICI. In this paper, we propose the optimization of the reference vector that minimizes the upper-bound of residual ICI power. Secondly, the iterative IA that designs the direction of transmit and receive filter is proposed to minimize the residual ICI as well as maximize the desired signals. Moreover, we propose the user scheduling method combined with proposed IA schemes which provides the multiuser diversity gain in multi-cell environments. Finally, the performance gain of the proposed IA algorithms compared with the existing IA are analyzed and demonstrated by simulation results.

• Journal of The Korean Association of Information Education
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• v.12 no.3
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• pp.267-274
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• 2008

A neural network is a modeling technique useful for finding out hidden patterns from data through repetitive learning process and for predicting target values for new data. In this study, we built multilayer perceptron neural networks for prediction of the students' computer literacy based on their personal characteristics, home and social environment, and academic record of other subjects. Prediction performance of the network was compared with that of a widely used prediction method, the regression model. From our experiments, it was found that personal characteristic features best explained computer proficiency level of a student, whereas the features of home and social environment resulted in the worse prediction accuracy among all. Moreover, the developed neural network model produced far more accurate prediction than the regression model.