S-ARQ: A New Truncated ARQ for IP-Based Wireless Network

Youngkyu Choi,오성준,Sunghyun Choi 한국통신학회 2010 Journal of communications and networks Vol.12 No.2

Automatic Repeat reQuest (ARQ) is a very effective technique against transmission error at the medium access control (MAC) layer. An erroneous MAC protocol data unit can be typically retransmitted within a given limit. In order to improve the IP-level performance, which directly affects the user-perceived quality-of-service (QoS), we propose a new truncated ARQ strategy,called MAC service data unit-based ARQ (S-ARQ), where the finite number of opportunities for retransmissions are shared by multiple fragments out of an IP datagram. We describe how SARQ can be implemented in a practical system, and then propose another variant of S-ARQ employing a functionality called early detection of failure. Basically, we evaluate the performance of SARQ in two different manners. First, assuming i.i.d. error process,we analyze both the probability of the delivery failure and the average delay of IP datagram. Then, we assess the performance of S-ARQ via simulation over a 2-state Markov channel.

IEEE 802.11 MAC-Level FEC scheme with retransmission combining

Choi, Sunghyun,Choi, Youngkyu,Lee, Inkyu IEEE 2006 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.5 No.1

In this paper, we evaluate and enhance the performance of a Forward Error Correction (FEC) scheme for IEEE 802.11 Medium Access Control (MAC). A novel retransmission combining technique is proposed to enhance the performance of the MAC-level FEC scheme.,We also identify the problem with the IEEE 802.11a physical (PHY) layer when it is used with the MAC-level FEC. A new PHY frame format, backward compatible with the original format, is proposed to resolve the problem. Finally, we analytically evaluate the error performance of the MAC-level FEC, and its enhanced performance via retransmission combining and new 802.11a PHY frame format in AWGN environment. Additionally, we present and discuss the results from simulations using TCP/UDP traffic in more realistic channel environments.

A Novel ARQ Strategy for Wireless Mobile IP Network

Youngkyu Choi,Sunghyun Choi 한국통신학회 2005 한국통신학회 학술대회 및 강연회 Vol.2005 No.4

Characteristics of Pig Carcass and Primal Cuts Measured by the Autofom Ⅲ Depend on Seasonal Classification

Jungseok Choi,Kimun Kwon,Youngkyu Lee,Eunyoung Ko,Yongsun Kim,Yangil Choi 한국축산식품학회 2019 한국축산식품학회지 Vol.39 No.2

The objective of this study was to investigate slaughtering performance, carcass grade, and quantitative traits of cuts according to seasonal influence by each month in pigs slaughtered in livestock processing complex (LPC) slaughterhouse in Korea, 2017. A total of 267,990 LYD (Landrace×Yorkshire×Duroc) pig data were used in this study. Results of slaughter heads, sex distribution, carcass weight, backfat thickness, grading class, total weight, and fat and lean meat percentages of each cut predicted by Autofom Ⅲ were obtained each month. The number of slaughtered pigs was the highest in early and late fall but the lowest in midsummer. Only in midsummer that the number of females was higher than that of castrates. During 2017, carcass weight was the lowest in late summer. Backfat thickness was in the range of 21–22 mm. In mid and late spring, pigs showed high 1+ grade ratio (37.05% and 36.15%, respectively). For traits of 11 cuts predicted by Autofom Ⅲ, porkbelly showed lower total weight, lean weight, and fat weight in midsummer to early fall but higher lean meat percentage compared to other seasons. Weights of deboned neck, loin, and lean meat were the highest in midfall compared to other seasons (p<0.05). In conclusion, characteristics of slaughtering, grading, and economic traits of pigs seemed to be highly seasonal. They were influenced by seasons. Results of this study could be used as basic data to develop seasonal specified management ways to improve pork production.

Shape-controlled percolation transition in 2D random packing of asymmetric dimers

Han, Youngkyu,Lee, Juncheol,Choi, Siyoung Q.,Choi, Myung Chul,Kim, Mahn Won IOP Publishing - Europhysics Letters 2015 Europhysics letters Vol.109 No.6

청소년 인권의식이 학교폭력에 미치는 영향에서 자아존중감 매개 효과

최영규(Choi youngkyu) 학습자중심교과교육학회 2021 학습자중심교과교육연구 Vol.21 No.1

본 연구는 청소년의 인권의식, 자아존중감, 학교폭력 간의 관계를 구조적인 인과관계에 의해 파악하고자 하는데 그 목적이 있다. 연구대상은 초등학교 5,6학년과 중학교에 재학 중인 학생이며 구조화 된 설문지를 사용하여 2017년 9월 1일부터 9월 22일까지 자료를 수집하였다. 자료처리는 SPSS WIN 22.0을 사용하였으며, 연구가설 검증을 위해 다중회귀분석을 실시하였다. 본 연구에 대한 결과는 인권의식은 자아존중감과 유의한 정적영향을 미치며, 학교폭력과는 유의한 부적영향을 미치는 것으로 나타났다. 자아존중감은 학교폭력과 유의한 부적영향을 미치는 것으로 나타내어 청소년의 인권의식이 높을수록 자아존중감이 높으며, 인권의식과 자아존중감이 높을수록 학교폭력이 낮은 것으로 확인되었다. 인권의식이 학교폭력에 미치는 영향에서 자아존중감은 부분매개효과를 가지는 것으로 확인되었다. 연구결과와 논의를 중심으로 실천적 제언, 정책적 제언, 후속연구에 대한 제언이 이루어졌다. The purpose of this study is to understand the relationship between adolescents’ human rights consciousness, self-esteem, and school violence through a structural causal relationship. The subjects of this study were students in the 5th and 6th grades of elementary school and middle school, and data were collected from September 1st to September 22nd, 2017 using a structured questionnaire. SPSS WIN 22.0 was used for data processing, and multiple regression analysis was performed to verify the research hypothesis. The results of this study showed that human rights consciousness had a significant positive effect on self-esteem and a significant negative effect on school violence. It was found that self-esteem had a significant negative effect on school violence. The higher the adolescent’s uman rights consciousness, the higher the self-esteem, and the higher the human rights consciousness and self-esteem, the lower the school violence. In the impact of human rights consciousness on school violence, it was confirmed that self-esteem has a partial mediating effect. Based on the research results and discussions, practical suggestions, policy suggestions, and suggestions for follow-up research were made.

Factors Affecting Interpersonal Competence of Nursing Students: Focused on Self-Assertiveness and Empathy

Choi, Jihea,Yoon, Heun Keung,Kim, Dahye,Kang, Minju,Park, Minji,Um, Sohui,Kim, Youngkyu,Kim, Eunsim 기본간호학회 2021 기본간호학회지 Vol.28 No.2

Purpose: Interpersonal competence, a key competence for patient-centered care by nurses, should be understood. Therefore, factors influencing the interpersonal competence of nursing students should be identified to explore and enhance their interpersonal relationships during the undergraduate educational curriculum for nursing educators. In this study factors influencing interpersonal competence, especially on self-assertiveness and empathy in nursing students were identified and analysed. Methods: A cross-sectional study design was used for the study in two Korean nursing colleges with similar baccalaureate nursing curricula. A total of 251 nursing students from freshman to senior year completed a questionnaire to measure related factors that were assumed to influence nursing students’ interpersonal competence. Data were collected from October 11~31, 2016. Study variables included self-assertiveness, empathy, interpersonal competence, and socio-demographic status. Multiple regression analysis was used for data analysis. Results: Nursing students’ interpersonal competence was explained by personality (β=.22), self-assertiveness (β=.16) and empathy (β=.38). The explanatory power of these predictors was 26.8% (p<.001). Conclusions: Nursing students’ interpersonal competence during the undergraduate nursing years can be enhanced by educational strategies that improve their interpersonal relationship as patient-centered care providers. Simultaneously, the attitude of the nurse educator is also important for nursing students who are to be treated as valuable learners and to improve students" empathy and self-assertiveness ability.

Deep Phenotyping in 1p36 Deletion Syndrome

Youngkyu Shim,Young Jun Go,Soo Yeon Kim,Hunmin Kim,Hee Hwang,Jieun Choi,Byung Chan Lim,Ki Joong Kim,Jong-Hee Chae 대한소아신경학회 2020 대한소아신경학회지 Vol.28 No.4

Purpose: Although 1p36 deletion syndrome is the most common terminal deletion syndrome, unexplained phenotypic variability still occurs. We aimed to delineate the phenotype of this syndrome in detail and to characterize the phenotype-genotype correlation. Methods: We retrospectively reviewed 15 patients diagnosed with 1p36 deletion syndrome confirmed by chromosomal microarray. Results: All 15 patients revealed delayed attainment of motor milestones and speech. Seven patients (46.7%) never walked alone and only two (13.3%) could express a simple two-word sentence. They all showed subsequent intellectual disability. Two patients with large deletions of both distal and proximal critical regions of the 1p36 region shared severe intellectual disability with Rett syndrome-like behavioral features. Seizures, although frequent (73.3%), were well-controlled except in one patient with infantile spasms. Facial dysmorphism (92.9%) and ventricular mild dilatation with corpus callosum anomaly (46.7%) were common. Heart problems were identified in 14 patients, including structural abnormalities and/or functional problems associated with the gene encoding PR domain-containing protein 16. Two patients developed severe cardiac dysfunction requiring heart transplantation in their late teens. One patient with a 400 Kb deletion partly overlapping with the gene encoding calmodulin-binding transcription activator 1 did not have facial dysmorphism and presented with mild developmental delay and ataxic gait. One patient had a choledochal cyst, which was resected due to neonatal cholestasis. Conclusion: Although the phenotype of 1p36 deletion syndrome is quite consistent with previous reports, additional manifestations such as certain behavioral features, ataxic gait, and severe cardiac dysfunction at an early age should be considered.

호텔 식음료부문의 공동브랜딩 도입에 관한 연구

김영규,최영준 한국식생활문화학회 2005 韓國食生活文化學會誌 Vol.20 No.2

It is the aim of this study to identify and develop improved management practice and competitive edge through co-branding which has been adopted extensively in the States. There is no universally accepted definition of co-branding. The term has been used interchangeably with labels such as brand alliance and composite branding. This study is exploratory in nature and at best a pilot study as few academic research are found dealing with actual cases between hotels and restaurant companies in Korea. Through related literatures reviews and research findings, this study will provide valuable insight as to the methods and activities of co-branding and a framework to help industry professions identify co-branding opportunities to enhance the productivity.

IEEE 1500 표준 기반의 효율적인 프로그램 가능한 메모리 BIST

박영규(Youngkyu Park),최인혁(Inhyuk Choi),강성호(Sungho Kang) 대한전자공학회 2013 전자공학회논문지 Vol.50 No.2

Systems-On-Chips(SoC)에서 내장 메모리가 차지하는 비중은 비약적으로 증가하여 전체 트랜지스터 수의 80%~90%를 차지하고 있어, SoC에서 내장된 메모리에 대한 테스트 중요성이 증가하고 있다. 본 논문은 다양한 테스트 알고리즘을 지원하는 IEEE 1500 래퍼 기반의 프로그램 가능한 메모리 내장 자체 테스트(PMBIST) 구조를 제안한다. 제안하는 PMBIST는 March 알고리즘 및 Walking, Galloping과 같은 non-March 알고리즘을 지원하여 높은 flexibility, programmability 및 고장 검출률을 보장한다. PMBIST는 최적화된 프로그램 명령어와 작은 프로그램 메모리에 의해 최적의 하드웨어 오버헤드를 가진다. 또한 제안된 고장 정보 처리 기술은 수리와 고장 진단을 위해 2개의 진단 방법을 효과적으로 지원하여 메모리의 수율 향상을 보장한다. As the weight of embedded memory within Systems-On-Chips(SoC) rapidly increases to 80-90% of the number of total transistors, the importance of testing embedded memory in SoC increases. This paper proposes IEEE std. 1500 wrapper based Programmable Memory Built-In Self-Test(PMBIST) architecture which can support various kinds of test algorithm. The proposed PMBIST guarantees high flexibility, programmability and fault coverage using not only March algorithms but also non-March algorithms such as Walking and Galloping. The PMBIST has an optimal hardware overhead by an optimum program instruction set and a smaller program memory. Furthermore, the proposed fault information processing scheme guarantees improvement of the memory yield by effectively supporting three types of the diagnostic methods for repair and diagnosis.