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Correlated Downlink-to-Uplink Interference Suppression for Full-Duplex C-RAN Systems
Shin, Cheolkyu,Park, Seok-Hwan IEEE 2019 IEEE Transactions on Vehicular Technology VT Vol.68 No.3
<P>In full-duplex cloud radio access network systems, the uplink received signal of each remote radio head (RRH) contains downlink-to-uplink (D2U) interference signal which is a linear combination of the transmit signals of nearby RRHs including itself. Since the fronthaul links that connect RRHs to a baseband processing unit (BBU) have finite capacity, the RRHs forward quantized versions of the uplink received signals to the BBU. To improve the fidelity of the quantization, it is important to suppress the impact of the D2U interference signals prior to the quantization. This paper tackles the problem of jointly optimizing the D2U interference suppression and fronthaul quantization strategies with the goal of maximizing the sum rate of uplink user equipments. To tackle the formulated non-convex problem, we derive an iterative algorithm based on the successive convex approximation approach. To save the complexity, a simpler algorithm, which non-iteratively pre-fixes the D2U interference suppression matrices, is also proposed. Extensive numerical results confirm the advantages of the proposed schemes compared to conventional schemes.</P>
High-Throughput Low-Complexity Link Adaptation for MIMO BIC-OFDM Systems
Cheolkyu Shin,Hyounkuk Kim,Kyeong Jin Kim,Hyuncheol Park IEEE 2011 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.59 No.4
<P>This paper introduces a new link adaptation (LA) approach called the adaptive modulation, coding, and spatial mode (AMCS) scheme for multiple-input multiple-output bit-interleaved coded orthogonal frequency division multiplexing (MIMO BIC-OFDM) systems. The AMCS technique can provide both minimal performance degradation and significant throughput gain by controlling the spatial streams. With this technique, we can derive a simple and accurate closed-form expression of an instantaneous bit error rate (I-BER). Based on the I-BER, the proposed AMCS scheme chooses an appropriate modulation, coding, and spatial mode (MCS) type that improves the system performance while satisfying the quality of service (QoS) requirement. A simplified MCS type search method is also proposed, which allows the receiver to effectively select a MCS type and then send it back to the transmitter by using only a small amount of information bits. The simulation results confirm the superiority of the proposed AMCS approach over conventional LA schemes in trading high-throughput for reduced complexity.</P>
PHY-Supported Frame Aggregation for Wireless Local Area Networks
Cheolkyu Shin,Hyuncheol Park,Kwon, Hyuck M. IEEE 2014 IEEE TRANSACTIONS ON MOBILE COMPUTING Vol.13 No.10
<P>An aggregate medium access control (MAC) service data unit (A-MSDU) contains multiple subframes with a single sequence number. Hence, it has a major drawback in environments with high error rates because if any subframes are corrupted, then the entire A-MSDU will be lost. In addition, performance of the A-MSDU depends strongly on the choice of parameters, such as frame size, modulation level, coding rate, and spatial mode. In this paper, a novel link-adaptation mechanism, dubbed physical (PHY)supported frame aggregation (PSFA), is proposed over IEEE 802.11 networks, and its performance is analyzed. The proposed PSFA technique is based on a cross-layer interaction that enables joint optimization of various parameters between the PHY and MAC layers. This paper derives a new packet error rate (PER) expression for convolutionally coded multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems as an example. Then, this PER expression is used to efficiently estimate the link quality, given the channel conditions and system parameters, and most importantly, it is able to facilitate a parametric study of the cross-layer interaction. In the proposed PSFA algorithm, we present a rule for selecting the parameters so that MAC throughput is maximized. It is shown analytically and verified using Monte Carlo simulations that this choice of parameters can improve throughput performance significantly and also ensure quality of service (QoS) requirements compared to existing conventional algorithms.</P>
( Cheolkyu Park ),( Yong Soo Kwon ),( Hong Joon Shin ),( Boram Lee ),( Hee Jung Ban ),( Injae Oh ),( Kyusik Kim ),( Yuil Kim ),( Sung Chul Lim ),( Young Chul Kim ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1
Background: Understanding of the bacteriology is critical in treatment of pleural infection. However, there are few studies about pathogens of pleural infection in Korea. This study aimed to determine microbiologic characteristics of pleural infection and identify predictive factors associated with mortality. Methods: We performed a retrospective study analyzing 114 cases of parapneumonic effusion with 134 micro-organisms. We examined pleural uid cultures using two culture systems, BACTEC blood culture and conventional method. Results: Of all isolated organisms, the most frequent pathogen was streptococcal species (35.8%) followed by staphylococci (19.4%), anaerobes (15.7%) and gram negatives (9.0%). In 73 specimens using both culture systems, BACTEC blood culture showed higher culture-positive rate (94.5%) than conventional method (35.6%). Streptococci were main organisms in conventional culture (48.4%), community-acquired infection (58.7%) and all susceptible, whereas staphylococci were major isolates in BACTEC blood culture (28.0%), hospital-acquired infection (33.8%) and drug-resistant organisms (58.8%). Smoking, interventions (pigtail, tube thoracostomy, intrapleural fi brinolytics, surgery), and severity score (CURB-65) were signifi cantly associated with 30-day mortality in univariate analysis. In multivariate analysis, tube thoracostomy (aOR 0.158, 95% CI 0.051 0.489, p=0.001), smoking (aOR 6.958, 95% CI 1.882 25.720, p=0.004) and CURB-65 =2 (aOR 4.204, 95% CI 1.345 13.136, p=0.014) weresignifi cant predictive factors for mortality. Conclusions: Common pathogens of pleural infection in Korea were streptococcal species, staphylococci, and anaerobes. Tube thoracostomy, smoking, and CURB-65 =2 could be predictive factors for death in pleural infection.
대학생의 무도수련이 성취목표성향과 운동몰입 및 자기효능감에 미치는 영향
조철규 ( Cheolkyu Cho ),신민철 ( Minchul Shin ) 사단법인 아시아문화학술원 2021 인문사회 21 Vol.12 No.4
본 연구는 대학생의 무도수련이 성취목표성향과 운동몰입 및 자기효능감에 미치는 영향을 규명하는데 목적이 있다. 이를 위하여 2021년 4~5월까지 광주와 전남 소재 대학에서 경찰 및 경호전공 대학생들을 모집단으로 선정한 후 설문조사를 실시하여 자료를 분석하였다. 분석결과 첫째, 무도수련을 통한 성취목표성향은 운동몰입의 모든 요인에 유의미한 정(+)의 영향을 미치는 것으로 나타났다. 둘째, 무도수련을 통한 성취목표성향은 자기효능감의 모든 요인에 유의미한 정(+)의 영향을 미치는 것으로 나타났다. 셋째, 무도수련을 통한 운동몰입은 자기효능감의 모든 요인에 유의미한 정(+)의 영향을 미치는 것으로 나타났다. 따라서 학생들의 성취목표성향을 고려하여 다양한 교육방안 및 지도를 통하여 학생들의 진로 및 취업지도에 활용한다면 진취적이고 창의적인 인재를 양성하는데 도움이 될 것으로 사료된다. The objective of this study is to examine the effects of martial arts training on the achievement goal orientation, exercise commitment, and self-efficacy of university students. For this, after selecting the university students majoring in police & security services of universities in Gwangju and Jeonnam region as a population, from April to May 2021, this study conducted a survey, and then analyzed the collected data. In the results of the analysis, first, the achievement goal orientation through martial arts training had significantly positive (+) effects on every factor of exercise commitment. Second, the achievement goal orientation through martial arts training had significantly positive (+) effects on every factor of self-efficacy. Third, the exercise commitment through martial arts training had significantly positive (+) effects on every factor of self-efficacy. Thus, if such various education measures and guidance are used for career and employment guidance by considering the students’ achievement goal orientation, it would be helpful for cultivating the progressive and creative talent.
캘리퍼 바디 적용 소재인 A357에 대한 기초물성 테스트에 관한 연구
신상훈(Sanghun Shin),정상균(Sangkyun Jung),정철규(Cheolkyu Jeong),박미자(Mija Park),이창호(Gilryong Hong) 한국자동차공학회 2019 한국자동차공학회 부문종합 학술대회 Vol.2019 No.5
Brakes are a key part of vehicle safety. In addition to core functions such as braking power and reliability, brakes are also required to improve fuel economy, reduce weight for carbon dioxide reduction, improve ride comfort, improve appearance, and improve the structure. To this end, the existing brake caliper body is made of main steel, and a light weight caliper body using aluminum is required in accordance with the global trend of improvement of fuel efficiency and environmental regulation. In this study, basic property test of caliper body using A357 material is performed The results were analyzed.
Electronic structure of (Ge2Sb2Te5)1−x(In3SbTe2)x investigated by x-ray photoelectron spectroscopy
Benayad, Anass,Kang, YounSeon,Shin, Hyun-Joon,Kim, Kihong,Suh, Dong-Seok,Kim, KiJoon,Kim, CheolKyu,Lee, Tae-Yon,Noh, Jin-Seo,Lee, JaeCheol,Khang, YoonHo American Institute of Physics 2009 JOURNAL OF APPLIED PHYSICS - Vol.106 No.4