우리나라 농촌 사회개발의 당면과제

조중기 中央大學校經營大學 1969 經營論集 Vol.28 No.-

우리나라 농촌 개발의 당면과제

조중기 中央大學校經營大學 1969 經營論集 Vol.28 No.-

정보보호 관리체계 인증 취득 후 기업가치의 변화에 관한 연구

조중기,최상현 한국융합학회 2016 한국융합학회논문지 Vol.7 No.6

본 연구는 ISMS인증 취득 후 기업의 성과를 측정하여 기업에게 어떤 영향을 미치는지를 정량적으로 분 석하였다. 본 연구에서는 사건연구방법론을 사용하였으며, 기업성과 중에서 기업의 가치에 대한 변화를 측정하기 위해 주가 정보를 활용하여 특정한 사건이 기업의 가치에 미치는 영향에 대해 초과수익률을 통해 분석하였다. ISMS 인증을 취득한 기업을 대상으로 ISMS 인증 취득 후에 초과수익률이 발생한 정도에 대한 분석을 시도하였으 며, 나아가 초과수익률을 3가지 상태인 증가, 유지, 감소로 분류하였으며, 집단별로 군집분석을 하였다. 본 연구의 결과는 ISMS 인증 성과에 대한 정량적 측정이 가능할 수 있고, 이를 통해 정보 보호에 대한 체계적인 활동을 요구 할 수 있으며, 나아가 기업의 정보보호 활동을 하는데 있어 도움이 될 것으로 기대한다. This study analyzed quantitative effects of ISMS certification. To measure the company value change the stock data was used and the methodology of event study was also applied. Event study methodology is a method of analyzing the effects of information or public announcement about certain events on the stock market through abnormal return of stock price. First, ISMS certification was acquired followed by the measurement of abnormal excess return of company. Based on the increase or decrease of abnormal excess return, the group was classified. There are 3 types of groups("Increase", "Reduce", "Maintain"). Next, the cluster analysis was performed for each group. Cluster analysis or clustering is the task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense or another) to each other than to those in other groups(clusters). The purpose of this study is to have a quantitative measurement of performance of ISMS certification. So, the result of this study will be promoted a company's ISMS certification acquisition. And it would further be beneficial to your company's information security activities.

삼축압축시험에 의한 자기력이 적용된 철가루 혼합 사질토의 전단강도특성 연구

조중기,장병욱,허준,김성필 한국농공학회 2007 한국농공학회논문집 Vol.49 No.6

Strain-stress behavior of soil is of importance in dealing with geo-techniques which relate to bearing capacity, slope stability, earth pressure and many geo-technical problems. So understanding mechanism of the behavior and reinforcing soil to the required state has been an issue for many years. This paper presents the possibility of magnetic force in enhancing shear strength. To analyze the reinforcing effect, triaxial compression tests were performed on two sets of steel-sand mixtures, one of which is influenced by permanent magnet, NdFeB. With magnetic force under 50kPa confining pressure, maximum shear strengths increased according to steel percentages but under 100kPa, no significant changes in maximum shear strengths occurred. Therefore the analysis by Mohr's circles indicates that magnetic force converts the shearing characteristics of sand into those of clay. 본 연구에서는 자기력이 사질토의 응력-변형률 거동에 어떠한 영향을 미치는지 분석하기 위하여 철가루와 주문진 표준사를 일정한 중량비로 혼합시킨 혼합시료에 대해서 철가루 함량비를 달리한 후, 2800-3800G의 네오디움 영구자석을 이용하여 자기력을 변수로 설정한 조건으로 삼축압축시험을 실시하였다. 삼축압축시험은 50kPa, 100kPa 두 가지 구속압에 대하여 압밀배수(CD) 모드로 진행되었으며 0.167%/min의 속도의 응력제어방식으로 총 변형률 15%에서 파괴를 종료시켰다. 그 결과를 요약하면 다음과 같다.

들은 만큼 보고, 보는 만큼 행동한다

조중기 지역재단 2009 지역리더 Vol.6 No.-

자기력이 적용된 철가루 혼합 사질토의 전단강도특성 연구

조중기,장병욱,김성필,허준,Cho, Joong-Ki,Chang, Pyeong-Wook,Kim, Seong-Pil,Heo, Jun 한국농공학회 2007 한국농공학회논문집 Vol.49 No.6

Strain-stress behavior of soil is of importance in dealing with geo-techniques which relate to bearing capacity, slope stability, earth pressure and many geo-technical problems. So understanding mechanism of the behavior and reinforcing soil to the required state has been an issue for many years. This paper presents the possibility of magnetic force in enhancing shear strength. To analyze the reinforcing effect, triaxial compression tests were performed on two sets of steel-sand mixtures, one of which is influenced by permanent magnet, NdFeB. With magnetic force under 50 kPa confining pressure, maximum shear strengths increased according to steel percentages but under 100 kPa, no significant changes in maximum shear strengths occurred. Therefore the analysis by Mohr's circles indicates that magnetic force converts the shearing characteristics of sand into those of clay.

모형 배양조 형태에 따른 단세포 조류의 비증식속도

곽중기(Jung Ki Kwak),김현주(Hyeon Ju Kim),이지현(Ji Hyun Lee),신가희(Ga Hee Shin),조만기(Man Gi Cho),한봉호(Bong Ho Han) 한국수산과학회 1998 한국수산과학회지 Vol.31 No.4

In the aquaculture industry, a photobioreactor (Pbr) with high productivity is a prerequisite for mass production of Chlorella sp., a feeding fry for Rotifer(Brachinous plicatilis). To enhance the productivity of Chlorella sp., model Pbrs such as Cylinder type, Spherical surface type, Half-spherical surface type, Plate type, Raceway pond type and Water-wheel type Pbr with different values of surface area exposed to light/culture volume(S/V) were manufactured, and maximum specific growth rate(μ_(max)) and productivity of Chlorella vulgaris 211-11b at 25℃, pH 7.0 and 12,000 lux were compared each other. The μ_(max) and productivity were not proportional to S/V. Among the 6 model Pbrs, Half-spherical surface type Pbr showed the highest μ_(max) and productivity as 2.206(day^(-1)) and 0.247(gℓ^-1day^(-1)).

Amenity를 고려한 농촌도로 계획요소의 AHP 평가

조중기 ( Cho Joong Ki ),장병욱 ( Chang Pyoung Wuck ),허준 ( Heo Joon ) 한국농공학회 2006 한국농공학회 학술대회초록집 Vol.2006 No.-

This paper briefly presents the result of survey using AHP(Analytical Hierarchy Process) to evaluate importance of factors including amenity which has not been considered in rural road planning. The survey was performed by 10 researchers in rural engineering major of Seoul National University. Among 10, 3 results over 0.1 in CR(consistency ratio) were excluded and the rest were used for calculating importance index by an arithmetic average. The results show that environment, user-convenience and amenity ranked orderly in large category are more important than other factors in planning rural road.

슈퍼 듀플렉스 스테인리스강(UNS S32506) 레이저 조관용접 튜브의 용접 후 열처리에 따른 부식거동

조동민(Dong Min Cho),박진성(Jin-seong Park),홍승갑(Seung Gab Hong),황중기(Joong-Ki Hwang),김성진(Sung Jin Kim) 한국표면공학회 2021 한국표면공학회지 Vol.54 No.3

The corrosion behaviors of laser-welded super duplex stainless steel tubes with post-weld heat treatment(PWHT) conditions(950, 1000, 1050, 1100 ℃ for 5 and 30 min) were evaluated by electrochemical potentiodynamic polarization and critical pitting temperature measurements. This study showed that the critical metallurgical factors affecting the degradation of corrosion resistance of a steel tube in as-welded condition were the unbalanced phase fraction(ferrite:austenite = 94:4), Cr₂N precipitation, and phase transformation from the austenite phase to ɛ-martensite(via stress-induced phase transformation). The improvement in the corrosion resistance of the welded specimen depends greatly on the PWHT conditions. The specimens after PWHT conducted below 1000 ℃ showed inferior corrosion resistance, caused by precipitation of the sigma phase enriched with Cr and Mo. At 1100 ℃ for a longer duration in PWHT, the ferrite phase grows, and its fraction increases, leading to an unbalanced phase fraction in the microstructure. As a result, pitting can be initiated primarily at the interface between the ferrite/austenite phase, particularly in base metal.

컴퓨터 시뮬레이션을 통한 치어 사육용 다단계 배양시스템의 개발 가능성 탐색

곽중기,조만기 한국생명과학회 2004 생명과학회지 Vol.14 No.2

The possibility for developing multistage culture system to cultivate larvae by computer simulation with basic experiments was investigated. This culture system was composed of 3 stages. At the 1st stage, Chlorella sp. were cultivated and at 2nd stage Chlorella sp. were supplied to rotifer (Brachionus plicatilis), and rotifer were supplied to larvae at the 3rd stage. In this study, Chlorella sp. were cultivated by batch culture to search for the possibility of continuous feeding to rotifer at 2 nd stage. The maximum specific growth rate ($\mu$$_{max}$) of Chlorella sp. at the logarithmic phase was 0.56 [1/day]. Rotifer was cultivated by fed-batch culture at the feeding rate of Chlorella sp., $10^3$, $10^4$, $10^{5}$ and $10^{6}$ [cells/rotiferㆍh] to search for the relation between the feeding rate of Chlorella sp. and the growth rate of rotifer. As the results, the minimum feeding rate of Chlorella sp. was 2.8 ${\times}$ $10^4$ [cells/rotiferㆍday] in the multistage culture system, then the change of rotifer concentration at 2nd stage was simulated by computer. The required amount of rotifer for the growth of larvae was also increased as the growth of larvae. On the 9th day of the culture, the rotifer uptake rate of larvae was 250 [cells/rotiferㆍday]. Based on these basic experiments and results, It was suggested that the possibility of multistage culture system to cultivate larvae with continuous feeding of Chlorella sp. and rotifer.r.