QT연장 증후군 환자에서 Head-Up Tilt Test에 의해 유발된 Torsades De Pointes 1례

전익수,차태준,김길수,김동완,김규종,김찬욱,김성만,주승재,이재우 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.8

제주도 지하수 질산염 농도의 시·공간적 변화 특성: 장기(1993-2015) 모니터링 자료의 평가

김호림(Ho-Rim Kim),오준섭(Junseop Oh),도현권(Hyun-Kwon Do),이경진(Kyung-Jin Lee),현익현(Ik-Hyun Hyun),오상실(Sang-Sil Oh),감상규(Sang-Kyu Kam),윤성택(Seong-Taek Yun) 대한자원환경지질학회 2018 자원환경지질 Vol.51 No.1

1993년부터 2015년까지 관측된 제주도 지하수 장기모니터링 관측정(N = 4,835)에서 수집된 지하수 수질자료(N = 21,568)를 기반으로 질산성질소의 시공간적 변동 특성을 평가하였다. 제주도 지하수의 질산성질소 농도의 중앙값은 2.5 mg/L로서 다른 국가나 대륙의 조사 결과에 비해 다소 높거나 유사한 것으로 나타났다. 또한 지하수 용도, 행정구역 및 고도 별로 유의한 차이를 보였다. 특히, 산간 지역에 비해 저지대 해안가에 위치한 농업 및 주거지역에서 농도가 높음을 확인하였다. Mann-Kendall 및 Sen’s slope 분석을 활용한 질산성질소 농도의 추세 분석 결과, 하류 저지 대에 비해 중산간지역에서의 질산성질소 농도 증가 경향이 뚜렷하였다. 제주도 내 토지 피복의 시계열 변화 특성과 결부 지어 보면, 중산간지역의 오염 증가 추세는 농업지역의 확장 등 인위적 활동 증가에 기인한 결과로 판단된다. 반면,기지정된 지하수자원특별관리구역에서는 전반적으로 질산성질소 농도의 감소 경향이 나타났는데, 이는 지하수 관리 측면에서 수질관리를 위한 적극적인 정책이 유효함을 시사한다. 본 연구에서는 제주도 지하수의 질산성질소 오염관리를 위한 적정 방안을 제안한다. The spatio-temporal variations of nitrate concentrations in groundwater of Jeju Island were evaluated by an analysis of time series groundwater quality data (N = 21,568) that were collected from regional groundwater monitoring (number of wells = 4,835) for up to 20 years between 1993 and 2015. The median concentration of NO 3 -N is 2.5 mg/L, which is slightly higher than those reported from regional surveys in other countries. Nitrate concentrations of groundwater in wells tend to significantly vary according to different water usage (of the well), administrative districts, and topographic elevations: nitrate level is higher in low-lying agricultural and residential areas than those in high mountainous areas. The Mann-Kendall trend test and Sen’s slope analysis show that nitrate concentration in mid-mountainous areas tends to increase, possibly due to the expansion of agricultural areas toward highland. On the other hand, nitrate concentrations in the Specially Designated Groundwater Quality Protection Zones show the temporally decreasing trend, which implies the efficiency of groundwater management actions in Jeju. Proper measures for sustainable groundwater quality management are suggested in this study.

축산분뇨중의 암모니아성 질소 제거

진양오,최성우,김성우,김익성,신남철,박승조 동아대학교 환경문제연구소 1999 硏究報告 Vol.22 No.2

The purpose of thus study were to investigate the proper conditions of struvite formation in synthetic wastewater and then to apply these conditions to effluent of anaerobic digester of livestock wastewater The conditions of struvite formation had been studied by many researchers. But a little conditions were different among them. Especially, according to suspended solid variation in livestock wastewater was investigated by few researchers. In experiment of synthetic wastewater, the proper conditions of struvite formation were pH 105, l50rpm of mixing rate, 10 minutes of reaction time, and 20 minutes of precipitation time. At same time, the ammonia nitrogen removal rates were about 99.7%, 95.5%, and 96% of synthetic wastewater, raw wastewater, and effluent of anaerobic digester of livestock wastewater at molar ratio of 2(Mg):l(N)2(P) respectively. The larger factor of NH₄/SS constant was, the more effective the removal rate of ammonium nitrogen, SS was, but the less effective COD_(cr), and TOC was. By using XRD analysis, the most certain compound in precipitate of synthetic wastewater was struvite.

문제해결 스타일이 혁신행동에 미치는 영향 - 핵심자기평가와 상사지원인식의 조절효과 검증을 중심으로 -

강순 ( Xun Jiang ),안성익 ( Ahn Seong Ik ),김성용 ( Kim Seong Yong ) 한국인적자원관리학회 2021 인적자원관리연구 Vol.28 No.1

기업 간 경쟁이 치열해지면서 통상적인 방법으로 기업이 경쟁에서 이길 수 없게 됨에 따라서 모든 조직들이 혁신을 간구하게 되었고, 이에 따라서 조직혁신을 증진하는 다양한 노력을 시도하는 가운데, 개인 수준의 행동을 통해 조직혁신을 도모하고자 혁신행동이 등장하게 되었다. 이런 배경 속에서 탄생한 혁신행동은 꾸준히 주목을 받아왔고, 그와 더불어 혁신행동을 증진하는 방안에 대해서 다양한 연구가 진행되어 오고 있다. 최근 혁신행동에 대한 종합적 문헌연구를 실시한 Kwon & Kim(2020)의 연구에서는 혁신행동의 선행요인으로서 개인특성의 중요성이 매우 낮게 다루어졌다. 이에 본 연구는 개인특성과 혁신행동간 관계를 다룬 기존 연구를 간략히 살펴보고, 연구의 방향을 설정하였다. 기존 연구에서는 성격과 혁신행동 간 관계에 대해서는 많이 연구되었으나, 이외의 개인특성과 혁신행동 간의 관계를 다룬 연구는 매우 부족한 편이다. 이에 본 연구는 혁신행동 연구 초기에 다루어졌던 개인특성인 문제해결 방식과 최근 주목받고 있는 개인특성인 핵심자기평가에 주목하게 되었다. 그리고 성격과 같은 개인특성과 혁신행동을 다룬 연구들은 혁신에 대한 성격의 주효과에도 많은 관심을 보였지만, 특성활성화 이론에 입각하여 성격 등의 특성이 혁신행동으로 발현되게 하는 상황요인에도 많은 관심을 보였다. 이러한 기존 연구 흐름에 따라서, 본 연구는 문제해결 스타일이 혁신행동으로 발현되는 과정에서 관련 상황요인으로 상사지원에 주목하고, 문제해결 스타일과 혁신행동 간의 관계에서 상사지원의 조절효과를 살펴보았다. 나아가, 특성활성화이론을 확장하여, 개인특성이 관련 행동으로 발현하는 과정에서 특정 개인이 이 관계를 증폭시킬 수 있는 가능성에 대해서 논의하고, 핵심자기평가가 문제해결 스타일과 혁신행동 간의 관계를 조절하는지 여부를 확인하였다. 이를 실증적으로 분석하기 위해서 중국의 공기업에 근무하는 228명으로부터 설문을 통해 자료를 수집하였고, 위계적 회귀분석을 통해 가설을 검증하였다. 분석결과, 문제해결 스타일의 두 하위 차원 중에서 직관적 문제해결 스타일만 혁신행동에 유의한 정(+)의 효과를 보였다. 또한 핵심자기평가는 혁신행동에 통계적으로 유의한 정(+)의 효과를 보였지만, 직관적 문제해결 스타일과 혁신행동 그리고 체계적 문제해결 스타일과 혁신행동 간 관계 모두에 대해서 유의한 조절효과를 보이지 않았다. 마지막으로 상사지원인식은 혁신행동에 대해서 유의한 정(+)의 효과를 보였고, 직관적 문제해결 스타일과 혁신행동 간에 유의한 조절효과를 보인 반면에 체계적 문제해결 스타일과 혁신행동 간 관계에 대해서 유의한 조절효과를 보이지 않았다. 이상의 결과를 놓고, 이론적 그리고 실무적 함의점에 대해서 논의하였다. As the competition among the firms, the conventional way of firms became useless for the competition and tried to search for innovation. In pursuing innovation, firm realized that firms’ innovation starts from individual members’ behaviors and created the concept of innovative behavior. Innovative behavior draw lots of attention and a large number of studies has been conducted up to now. Recent Kwon & Kim’s (2020) literature review on innovative behavior showed little attention to individual trait like personality. In this background, our study shortly reviewed on the studies about the relationship between personal trait and innovative behavior and set the direction of this study. After short review, we found that there is not a few studies about the relationship between personality and innovative behavior but little about the relationship between innovative behavior and the personal traits except personality. So we focused on the problem solving style which drew the attention as antecedents of innovative behavior at early stage of research on innovative behavior and core self-evaluation which are suggested relatively recently and very limitedly studied as the antecedents of innovative behavior. The studies on personal traits pay attention not only to their effects on consequences but also to the relevant situation that can activate the relationship between trait and trait relevant behavior following trait activation theory. In the vein, we also considered in the supervisory support as the potential moderating variables on the relationship between problem solving style and innovative behavior. For the empirical test, we collected data from the 228employees belong to Chinese public companies with survey and analyzed the relationship with hierarchical regression analysis. First, only intuitive problem solving style except systematic problem solving style showed significant positive effect on innovative behavior. Second, in the case of core self-evaluation, its main effect on innovative behavior was supported but none of its moderating effects on the two path from problem solving style to innovative behavior. Last, in the case of supervisory support, its main effect on innovative behavior was supported and the moderating effect on the path from intuitive problem solving style to innovative behavior was supported. On these results. We discussed the theoretical and practical implications.

부산지역 일부 약수터에 대한 ‘맛있고 건강한 물’의 지표 적용

김현실,김익성,박청길,곽명화,윤철종,박승조 동아대학교 환경문제연구소 2001 硏究報告 Vol.24 No.2

This study was performed to investigate the water quality of some natural mineral springs in Busan. Samples for this study were collected at fifty sites during a year. from March 2000 to February 2001. The overall tendency of mineral was Na>Ca>Mg>K, and the seasonal variation of each components were like this - Ca: Win>Spr>Sum>Aut, Mg: Spr>Win>Sum>Aut, Na: Sum>Aut> Spr>Win, K: Aut>Sum>Spr>Win The K and O index suggested by Hashimoto was followed : delicious water(58%) > not belong to any group(34%) > healthy and delicious water(6%) > healthy water(2%).

곡선형 강박스거더 도로교의 단면최적화에 관한 연구

김상효,조성범,정재익 연세대학교 산업기술연구소 1996 논문집 Vol.28 No.1

The steel-box girder decks are widely adopted for middle and long-span bridges due to many advantages, when comparing with other open-section girder types, such as higher torsional rigidity, better resistance against corrosion, etc. In current design practice, the design variables of steel-box girder are selected mainly on the basis of engineer's experience and direct observation. Then the assumed sections are checked for design limit states. Therefore, the resulted design sections are doubtful in the optimum viewpoint. To achieve more rational design, systematic design procedure is required, by which the design constraints on steel-box girders are satisfied and the design variables of minimum cost are obtained. Generally both bending moments by transverse loads and torsional moments by eccentric loadings are the most important load effects in curved steel-box girder bridges. Therefore, an optimization program is developed to consider the torsional moment in addition to other load effects. The efficiency of the developed program has been verified by redesigning some sections selected from existing bridge designs. The resulting optimum sections with discrete variables are found to be cost-saving and comparable with original sections. Based on the parametric studies performed for mainly radius of curvature on curved bridge and bridge width, some essential guidelines for rational design of curved steel-box girder bridges are suggested.

On the Mizohata Operator

김익찬,홍성관 제주대학교 1984 논문집 Vol.17 No.-

In this paper we prove: 1) au/at + it au/ax = f(x,t) has a unique c solution when f is analytic 2) Let f(x,t) ∈C_(c)^(∞) (R^(2)) have the following properties: f(x,t) = f(x,-t) for all (x,t)∈R^(2) ; the supp f ∩ [x-axis) = {(O,O)) ; ∬/R^(2) f(x,t) dxdt ≠ 0. Then au/at + it au/ax = f does not have c' solution.

셀룰라 오토마타 기반의 완전해싱

김한두,허성훈,문종익 인제대학교기초과학연구소 2002 자연과학 Vol.6 No.-

이 논문에서 셀룰라 오토마타를 이용한 완전해싱 방법을 제시하였다. In this paper we investigate the Cellular Automata-based perfect hashing scheme.

변형된 EM 알고리즘을 이용한 GMM 기반 문맥독립 화자식별 시스템의 성능향상

김성종,안종복,정익주 강원대학교 정보통신연구소 2005 정보통신논문지 Vol.9 No.-

In speaker identification systems, it was proved in previous other experimental theses that the performance of GMM is better than that of any other speaker modeling techniques. The EM algorithm is used to build a GMM-based speaker identification system. This paper introduces the modified EM algorithm to enhance the identification rate. The experiments examine algorithmic issues (initialization, variance limiting and model order selection). As a result of the experiments, the modified EM algorithm achieves 95.044% identification accuracy comparing with basic EM algorithm (94.605% identification accuracy) and is shown to outperform the basic EM algorithm.

Aerosol Reactor를 이용한 고분자 입자의 제조

김성익,김선근 중앙대학교 생산공학연구소 1992 생산공학연구소 논문집 Vol.1 No.1

Spherical polymer particles with narrow size distribution have been prepared by aerosol-phase polymerization. The aerosol-phase reactor has advantages over the conventional methods in the preparation of spherical, monodisperse particles with controllable size. The aerosol reaction system consisted of seed generator, boiler, condenser, reboiler, recondenser, reactor and particle collector in series. The polyurea particles were prepared by the reaction of TDI(toluene-2,4-diisocyanate) or HDI(hexamethylenediisocyanate) droplets with EDA(ethylenediamine) vapor. The use of seed(NaCl) nuclei helped the polymer particles smaller in size and made the size distribution of the particles narrower. The particle size increased substantially with boiler temperature and decrease slightly with increasing the carrier gas flow rate. Increase in reboiler temperature improved the monodispersity of the particle size. Sphericity and surface smoothness of the particles were improved by decreasing particle size and controlling the reaction rates. The coating of TiO₂on the surface of the preapared polymer paticles was carried out by condensing Ti(Oet)₄on the particle surface and subsequently reacting the liquid film with water vapor. The reaction system was also applied to prepare polyamide particles successfully.