Impact of health-related quality of life on survival after dialysis initiation: a prospective cohort study in Korea

( Jeonghwan Lee ),( Yong Chul Kim ),( Soie Kwon ),( Lilin Li ),( Sohee Oh ),( Do Hyoung Kim ),( Jung Nam An ),( Jang-hee Cho ),( Dong Ki Kim ),( Yong-lim Kim ),( Yun Kyu Oh ),( Chun Soo Lim ),( Yon Su 대한신장학회 2020 Kidney Research and Clinical Practice Vol.39 No.4

Background: The effect of each health-related quality of life (HRQOL) component on hemodialysis prognosis has not been well studied. We aimed to investigate the clinical factors associated with HRQOL and the effect of HRQOL after dialysis initiation on long-term survival in an Asian population. Methods: A total of 568 hemodialysis patients were included from a nationwide prospective cohort study. HRQOL was evaluated using the Kidney Disease Quality of Life (KDQOL) Short FormTM 1.3 at 3 months after dialysis initiation. The effect of each KDQOL item score on mortality was analyzed. Multivariable Cox analysis was performed after adjusting for age, sex, modified Charlson comorbidity index, and causes of primary kidney disease. Results: Old age, diabetes mellitus, high comorbidities, and low serum albumin levels were associated with poor physical health status. Decreased urine output was associated with both poor physical and mental health status. The scores of 3 indices in the kidney disease domain (effect of kidney disease, social support, and dialysis staff encouragement) showed significant associations with mortality, as did the 3 indices (physical function, physical role limitation, and body pain) in the physical health domain. Neither the 4 indices in the mental health domain nor the mental composite score showed a significant association with mortality. However, a high physical composite score was associated with decreased overall patient mortality (P = 0.003). The effect of physical composite score on survival was prominent among young or middle-aged groups. Conclusion: Poor physical health status 3 months after hemodialysis start correlates significantly with overall mortality.

시계열 예측을 사용한 버스 잔여좌석 예측 시스템

임정환(JeongHwan Lim),박성수(SeongSu Park),고승범(SeungBeom Go),김준태(JunTae Kim),김동호(DongHo Kim) 한국정보과학회 2017 한국정보과학회 학술발표논문집 Vol.2017 No.06

Improved Synapse Device With MLC and Conductance Linearity Using Quantized Conduction for Neuromorphic Systems

Lim, Seokjae,Sung, Changhyuck,Kim, Hyungjun,Kim, Taesu,Song, Jeonghwan,Kim, Jae-Joon,Hwang, Hyunsang IEEE 2018 IEEE electron device letters Vol.39 No.2

<P>In this letter, we demonstrate the conductive-bridging RAM (CBRAM) with excellent multi-level cell (MLC) and linear conductance characteristics for an artificial synaptic device of neuromorphic systems. Our findings show that inherent characteristics of CBRAM can achieve the linear conductance and MLC characteristics as a product of an integer unit of the conductance. However, uncontrolled metal-ion injection into the switching layer results in a significant degradation of device uniformity, leading to degradation in the classification accuracy. Thus, we introduce a multi-layer CBRAM configuration (Cu/HfO<SUB>2</SUB>/Ta/Cu<SUB>2</SUB>S/W) to control the ionic motion in electrolytes. As a result of device engineering, highly improved classification accuracy is achieved using CIFAR-10 data set.</P>

CMOS compatible low-power volatile atomic switch for steep-slope FET devices

Lim, Seokjae,Yoo, Jongmyung,Song, Jeonghwan,Woo, Jiyong,Park, Jaehyuk,Hwang, Hyunsang American Institute of Physics 2018 Applied Physics Letters Vol.113 No.3

산불 피해지 복원 방법이 임분 내 미세 기후에 미치는 영향

김정환 ( Jeonghwan Kim ),임주훈 ( Joohoon Lim ),박찬우 ( Chanwoo Park ),권진오 ( Jino Kwon ),최형태 ( Hyungtae Choi ) 한국농림기상학회 2015 한국농림기상학회지 Vol.17 No.3

본 연구는 산불 피해지에서 복원 방법 및 수종의 구성에 따라 미세 기후가 어떻게 변하는지에 관한 연구는 거의 이루어진 바 없어 산불 피해지에서 복원방법 및 임분의 구성에 따라 임분 내 기상 패턴이 어떻게 변화하는지에 대해 구명하고자 수행되었다. 본연구에서 사용된 독립 변수로 임분을 구성하는 수종의 종류와 생장, 임분 밀도, 그리고 피복율이며, 이에 따른 종속 변수로는 임분 내 광량, 기온, 습도, 토양 온도, 그리고 토양 수분 함량이었다. 기상 조건은 대부분 광 조건에 영향을 받는 종속 변수이나, 임분을 구성하는 수목의 생장과 피복률에도 변화하는 것으로 나타났다. 임분 내 습도는 임분 밀도와, 임분 내 기온과 수목의 수고와 음(-)의 상관 관계에 있는 것으로 나타나 임분 밀도와 수목의 생장이 증가할수록 임분 내부의 기온과 습도는 상대적으로 감소하는 경향을 보였다. 그러나 임분의 발달은 대부분 미세 기후의 전체 평균보다는 변동계수와 같은 편차를 줄이는 형태로 더 큰 영향을 주었으며, 수관 층의 수고와 임분 내 광량과 직접적인 관계에 있는 것을 감안하면(R2=0.87), 임분의 구조는 광량에는 직접적인 영향을, 다른 미세 기후에는 간접적인 영향을 준 것으로 사료된다. 한편 변동계수의 경우 삼척 지역이 고성 지역보다 상대적으로 높은 값을 보였으며, 수목의 생장에 따라 감소하는 경향을 보였다. 따라서 산불 발생 이후 시간 경과에 따라 상대적으로 안정된 상태를 지니는 것으로 해석되었다. 그러나, 현재 단계에서는 산불 피해 이후 숲의 발달에 따른 임분 내부의 기상 조건의 변화상을 뚜렷하게 확인하고 일반화하기에는 많은 어려움이 있어 이를위해서는 보다 긴 시간에 걸쳐 많은 지점에서의 기상조건과 임분 현황을 지속적으로 조사되어야 할 것이다. 이후 일반화된 자료를 활용한다면, 임분 구조와의 관계 해석은 물론, 하층 식생 출현 등에 대한 해석에 도움이 될 것으로 기대된다. The study was conducted to determine the effects of forest restoration methods and stand structure on solar radiation, air temperature, relative humidity, soil temperature, and soil water content, based on volume, in forest stand after forest fire. The changes of the micro-climate elements in naturally and artificially restored forest after forest fire were measured in Goseong and Samcheok, Gangwon province. Pinus spp. were commonly appeared in ridges, barren lands or planted areas of the study sites while the other areas were dominated by Quercus spp. In the early stage, trees in the naturally regenerated site grow better than the trees in artificially rehabilitated site. However, the growth ratio rapidly decreased by time passed in natural regeneration area. The environmental conditions (solar radiation, air temperature, relative humidity, soil temperature and soil water content) were significantly different by the regions and the methods (p<.05). However, the coefficients of variations of the environmental conditions were not significantly different at 95% confidence level. As the coverage and tree height in crown layer increased, the relative humidity and soil water content were increased while the temperature and solar radiation were decreased. Especially, the relative humidity, solar radiation, and soil water content were clearly affected by the tree height and coverage ratio (R2 means from 0.628 to 0.924). Even though the data should have collected at least more than 5 years in meteorological analysis, the two year results show some clear relationship between forest structure and microclimate elements.

Self-Limited CBRAM With Threshold Selector for 1S1R Crossbar Array Applications

Song, Jeonghwan,Woo, Jiyong,Lim, Seokjae,Chekol, Solomon Amsalu,Hwang, Hyunsang IEEE 2017 IEEE electron device letters Vol.38 No.11

<P>In this letter, we demonstrate a self-limited conductive-bridging random accessmemory (CBRAM) that removes the necessity for external current compliance in a one selector-one resistor (1S1R) architecture. The standard Ge2Sb2Te5 (GST) is used as a CBRAM switching layer. In addition, Te-rich GST is also considered. Their performance is then compared. Both samples exhibit self-limited on-current characteristics, and the on-currents of the standard GST and Te-rich GST are similar to 300 and similar to 20 mu A, respectively. The observed self-limited characteristics are caused by the Te in the GST layer because in the presence of Te, Cu tends to form a more stable CuTe phase that restrict Cu filament growth. Furthermore, to confirm the feasibility of crossbar array applications, the 1S1R device is evaluated using a Ag/TiO2-based threshold selector device reported in our previous work. Hence, we confirm leakage current reduction, a uniform resistance distribution, and stable retention characteristics in the 1S1R configuration with no external current compliance.</P>

An Analysis and Improvement Strategy of the Technology Transfer Efficiency for Public Research Institutes

Injong Lim,Jeonghwan Lee,Sang-Myung Lee 보안공학연구지원센터 2016 International Journal of Software Engineering and Vol.10 No.12

Public research institutes take major role in creating breakthrough technology development but most cases, fail to successfully commercialize it. This is very critical symptom in Korea where the government R&D expenditure is among top in the world, but its money value of commercialization is very low. In this study, we studied all Korean public research institutes to evaluate the efficiency of their technology development and technology transfer, showing the wide gap of two activities. In order to properly measure the efficiency, we make full use of input and output variables such as research/TLO human resources and expense, and research outputs such as patents and royalty revenue. In summary, we show that, in order to efficiently manage government-supported R&D, it is necessary to maximize the efficiency both for technology development and technology transfer of public research institutes.

고전 오류 정정부호 방식을 활용한 연속 변수 양자 키 분배 후처리 과정

임문수(Lim MoonSoo),신정환(Shin JeongHwan ),허준(Heo Jun) 한국통신학회 2017 한국통신학회 학술대회논문집 Vol.2017 No.1

ZPD 수준 판별 도구의 구안 및 타당화

김정환(JeongHwan Kim),임웅(Woong Lim),정은영(EunYoung Jeong) 한국교육평가학회 2007 교육평가연구 Vol.20 No.4

  Vygotsky의 근접발달영역(ZPD) 수준 판별 도구를 구안하여 타당화 하였다. ZPD 점수는 학습자가 제시된 힌트를 자율적으로 활용하여 해결하여 획득한 점수와, 힌트 없이 해결하여 획득한 점수간의 차이점수로 규정하였다. 타당화한 ZPD 검사도구는 기존 지능검사와 상관이 유의미하지 않았는데, ZPD의 귀납추론 검사 점수와 기존 지능검사 지수간의 상관이 유의미한 것으로 나타났다. 또한, 낮은 지능지수를 보이는 학습자들이 힌트를 활용하여 해결하는 ZPD 검사에서 비교적 높은 수행력을 보이는 것으로 밝혀졌다. 이로서 ZPD검사가 기존 지능검사에 의해 측정되기 어려운 수행력을 측정하는 것으로 확인되었다. 따라서 앞으로 ZPD검사를 적용한 역동적인 지능검사 도구 개발 가능성을 시사해주고 있다.   The purpose of this research was to design and validate ZPD test which has been constructed based on Vygotsky"s socio-cognitive theory. In ZPD test, a zone of proximal development was defined as an inverse proportional function that includes clues needed in achieving successful independent performance within a problem domain, maintaining acquired knowledges and skills, and transferring them to different problem types. The design procedure of ZPD test was as follows: First, the geometric analogy task and the number series completion task of the inductive reasoning domain were selected. Second, it was verified that Raven test and inductive reasoning test assessed the same abilities. Third, the similar difficulty level ZPD with Raven"s test was constructed and validated. The subjects of this study were 6th grade students in C elementary school. The results of this study were summarized as follows: First, there was no significantly meaningful correlation between ZPD test and conventional intelligent test. But there was significantly meaningful correlation between inductive reasoning in ZPD test and conventional intelligent test scores. This implied that conventional intelligent test and ZPD test measured somewhat different performance. Second, the subjects who had lower intelligent scores showed as the same score level as those who had higher intelligent scores. This study suggested that human intelligent should be extended to potential development level. And this ZPD test could complement other conventional intelligent tests. This study suggested the possibility of developing dynamic evaluation tool.

A High-Speed CMOS Image Sensor With Column-Parallel Two-Step Single-Slope ADCs

Seunghyun Lim,Jeonghwan Lee,Dongsoo Kim,Gunhee Han IEEE 2009 IEEE transactions on electron devices Vol.56 No.3

<P>This paper proposes a column-parallel two-step single-slope (SS) ADC for high-speed CMOS image sensors. Error correction scheme to improve the linearity is proposed as well. A prototype sensor of 320 times 240 pixels has been fabricated with a 0.35-mum CMOS process. Measurement results demonstrate that the proposed ADC can achieve the conversion time of 4 mus , which is ten times faster than the conventional SS ADC. The proposed error correction effectively removes the dead band problem and yields DNL of +0.53/ -0.78 LSB and INL of +1.42/ -1.61 LSB. The power consumption is 36 mW from a supply voltage of 2.8 V.</P>