조선소에서의 시뮬레이션 기반 생산에 관한 연구 : 선표 계획 검증을 중심으로

이동건,오대균,Lee, Dong-Kun,Oh, Dae-Kyun 해양환경안전학회 2014 해양환경안전학회지 Vol.20 No.1

조선소의 생산성은 제한된 자원을 얼마나 효율적이고 체계적으로 관리하고 사용하는가에 달려있다. 최근 들어 조선소에서는 생산관리 시스템을 고도화하기 위해 시뮬레이션 기법을 적용한 연구가 활발히 진행되고 있다. 본 논문에서는 시뮬레이션 기법을 생산관리에 적용한 조선소의 시뮬레이션 기반 생산 개념을 연구하였다. 이는 조선소 현장에서 경험과 직관에 의한 의사결정을 지양하고, 정량적이고 구체적인 데이터에 기반을 둔 개선방안을 확립할 수 있게 한다. 본 논문에서는 조선소의 생산 계획 중 선표 계획 영역에 대한 시뮬레이션 적용 연구를 수행하였으며, 이를 위해 조선소의 생산 계획 프로세스와 시스템을 분석하고 상용 시뮬레이션 소프트웨어를 이용한 시뮬레이션 시스템의 설계를 수행하였다. 이러한 시뮬레이션 시스템은 현재 조선소 생산관리 시스템의 운용환경을 고려하여 웹 환경에서 운용가능한 구조를 갖고 있으며, 이를 통해 조선소에서는 보다 손쉽게 생산 계획을 시뮬레이션하고 결과를 분석함으로써 보다 신뢰도 높은 생산 계획을 수립할 수 있을 것으로 기대한다. Productivity improvement of a shipbuilding company depends on how efficiently its limited resources are managed and utilized. Recently, research on modeling and simulation (M&S) to support shipyard production management system has been being under study. The production management based on M&S rejects decision making on experience, and it can establish productivity improvement method based on quantitative and specific data. In this paper, M&S is applied to the long-term plan as a part of the production planning in shipyards. To this end, the long-term plan processes and related management systems are analyzed. Based on the analysis, a simulation model and an application system using commercial simulation software are suggested. And basic structure of the suggested system is based on web technology such as Rich Internet Application, web services protocol for compatibility with existing shipyard enterprise systems. Utilizing the results of this study, it is expected that shipyard production planners can settle down work flow, in which one can establishes the production plan, simulates the plan, and analyzes the results, enabling a more reliable production plans.

사용종료매립지 정비를 위한 흙-시멘트 연직차수벽의 차수성능 평가

이동건,안조환,권기욱,구자공,배우근,Lee, Dong-Geon,Ahn, Jo-Hwan,Kwon, Ki-Wook,Koo, Ja-Kong,Bae, Woo-Keun 한국지하수토양환경학회 2011 지하수토양환경 Vol.16 No.1

This study was conducted to evaluate the performance of soil-cement walls (SCWs) to control leachate from a leaking landfill site. Tracer tests revealed that the SCW was effective to control groundwater seepage. Approximately two-months of curing period appeared to be sufficient to ensure thorough containment of landfill leachate, although a three-week period was not enough. The water quality of the monitoring wells after construction of the SCWs met the groundwater quality standard of the korean Waste Management Act, except for bacteria and coliform groups. Also an analysis of a spring water around the landfill showed that the concentrations of ammonia, inorganic nitrogen and soluble manganese which had been common contaminants in the spring water decreased dramatically after constructing the walls. Therefore, the results suggested that a SCW can be an attractive method to control leachate from a leaking landfill site.

MgB₂ 초전도 특성에 대한 나노 Fe_xC 첨가 효과

이동건,이지현,전병혁,박순동,엄영랑,박해웅,김찬중,Lee, Dong-Gun,Lee, Ji-Hyun,Jun, Byung-Hyuk,Park, Soon-Dong,Uhm, Young-Rang,Park, Hai-Woong,Kim, Chan-Joong 한국분말야금학회 2012 한국분말재료학회지 (KPMI) Vol.19 No.2

The effects of nano $Fe_xC$ addition to superconducting properties of $in$ $situ$ processed $MgB_2$ superconductors was examined. 0.1 wt.% and 1 wt.% nano $Fe_xC$ powders were mixed with boron and magnesium powders by ball milling. The powder mixtures were made into pellets by uniaxial pressing. The pellets were heat-treated at $700^{\circ}C-900^{\circ}C$ in argon atmosphere for $MgB_2$ formation. It was found by powder X-ray diffraction that the raw powders were completely converted into $MgB_2$ after the heat treatment. The superconducting transition temperature ($T_c$) and critical current density ($J_c$), estimated from susceptibility-temperature and $M-H$ curves, were decreased by nano $Fe_xC$ addition. The $T_c$ and $J_c$ decrease by nano $Fe_xC$ addition are attributed to the incorporation of iron and carbon with $MgB_2$ lattices (Fe substitution for Mg and C substitution for B) due to the high reactivity of the nano $Fe_xC$ powder.

광학 오류 주입 공격에 강인한 몽고메리 지수승 기반 RSA 하드웨어 구현

이동건,최용제,최두호,김민호,김호원,Lee, Dong-Geon,Choi, Yong-Je,Choi, Doo-Ho,Kim, Minho,Kim, Howon 한국정보통신학회 2013 한국정보통신학회논문지 Vol.17 No.1

본 논문에서는 RSA를 몽고메리 지수승 기반의 하드웨어로 구현함에 있어 광학 오류 주입 공격을 탐지할 수 있는 기술을 제안한다. 본 기법은 몽고메리 곱셈 기반의 연산에서 메모리 입출력에 오류가 주입되었는지 확인하기 위해 무결성 검증 절차를 구현하였으며, 곱셈 연산에는 사용되는 로직에 광학 오류 주입 탐지 기법을 적용함으로써 안전한 지수승 연산을 가능하도록 하였다. 제안한 기법은 다양한 오류에 대하여 안전한 것으로 확인되었으며, 암호화 연산 수행시간에 영향을 미치지 않으며, 전체 면적 대비 3% 미만의 오버헤드로 구현 가능하다. In this paper, we propose a novel optical fault detection scheme for RSA hardware based on Montgomery exponentiation, which can effectively detect optical fault injection during the exponent calculation. To protect the RSA hardware from the optical fault injection attack, we implemented integrity check logic for memory and optical fault detection logic for Montgomery-based multiplier. The proposed scheme is considered to be safe from various type of attack and it can be implemented with no additional operation time and small area overhead which is less than 3%.

울릉분지 시추공 분석 자료를 이용한 가스하이드레이트 함유층의 3차원 공간 물성 분포 추정

이동건,신효진,임종세,Lee, Dong-Gun,Shin, Hyo-Jin,Lim, Jong-Se 한국에너지학회 2013 에너지공학 Vol.22 No.2

이 연구에서는 2007년, 2010년에 수행한 울릉분지 1, 2차 시추 지역의 시추공(UBGH1-1, UBGH1-4, UBGH1-9, UBGH1-10, UBGH1-14, UBGH2-2-1, UBGH2-2-2, UBGH2-6, UBGH2-9, UBGH2-10, UBGH2-11)에서 취득한 물리검층 및 코어분석 자료로 추정한 가스하이드레이트 함유층 주요 물성 자료를 활용하여 불균질성을 반영할 격자 수준의 3차원 공간 분포 모델링을 수행하였다. 가스하이드레이트 함유층 내 퇴적상의 공간 분포 추정을 위하여 퇴적상 추정 자료를 각 시추공별로 3차원 격자셀에 입력하고 순차지표시뮬레이션으로 3차원 분포를 모델링하였다. 가스하이드레이트 함유층의 공극률과 가스하이드레이트포화율은 퇴적상 분포 모델을 기반으로 순차가우스시뮬레이션을 통해 3차원 공간 물성 분포를 추정하였다. Drilling expedition #1 in 2007 and drilling expedition #2 in 2010 were performed for gas hydrate resources evaluation and optimal site selection of pilot test in Ulleung basin, East Sea, Korea. This study presents to build the 3D spatial distribution models using the estimated sedimentary facies, porosity, and gas hydrate saturation derived by well logs and core analysis data from UBGH1-4, UBGH1-9, UBGH1-10, UBGH1-14, UBGH2-2-1, UBGH2-2-2, UBGH2-6, UBGH2-9, UBGH2-10 and UBGH2-11. The objective of 3D spatial distribution modeling is to build a geological representation of the gas hydrate-bearing sediment that honors the heterogeneity in 3D grid scale. The facies modeling is populating sedimentary facies into a geological grid using sequential indicator simulation. The porosity and gas hydrate saturation modeling used sequential Gaussian simulation to populate properties stochastically into grid cells.

수평관내 이산화탄소의 증발 압력강하

이동건,손창효,오후규,Lee Dong-Geon,Son Chang-Hyo,Oh Hoo-Kyu 한국마린엔지니어링학회 2005 한국마린엔지니어링학회지 Vol.29 No.5

The evaporation pressure drop of $CO_2$ (R-744) in a horizontal tube was investigated experimentally. The experiments were conducted without oil in a closed refrigerant loop which was driven by a magnetic gear pump. The main components of the refrigerant loop are a receiver, a variable-speed pump. a mass flow meter, a pre-heater and evaporator (test section). The test section consists of a smooth. horizontal stainless steel tube of 7.75 mm inner diameter. The experiments were conducted at mass flux of 200 to $500\;kg/m^{2}s$, saturation temperature of $-5^{\circ}C\;to\;5^{\circ}C$. and heat flux of 10 to $40\;kW/m^2$. The test results showed the evaporation pressure drop of $CO_2$ are highly dependent on the vapor qualify, heat flux and saturation temperature. The evaporation pressure drop of $CO_2$ is very lower than that of R-22. In comparison with test results and existing correlations. the best fit of the present experimental data is obtained with the correlation of Choi et al. But existing correlations failed to predict the evaporation pressure drop of $CO_2$. Therefore, it is necessary to develop reliable and accurate predictions determining the evaporation pressure drop of $CO_2$ in a horizontal tube.

남녀 대학생에서 십선혈(十宣穴) 사혈(瀉血)이 혈압, 체온 및 맥박수에 미치는 영향

이동건,정원제,이현진,조현석,김경호,김갑성,Lee, Dong-Gun,Jeong, Won-Je,Lee, Hyun-Jin,Cho, Hyun-Seok,Kim, Kyung-Ho,Kim, Kap-Sung 대한침구의학회 2008 대한침구의학회지 Vol.25 No.4

Objectives : Sypsun-points are located at the tips of all fingers, 0.1 chon(寸) from the finger nails, totaling 10 points on both hands. These points have been used for emergency care, fainting, epilepsy, cerebrovascular accidents, hypertension, unconsciousness, high fever etc. in oriental medicine. The most common technique is bleeding with a needle at these points. We investigated whether Venesection at the Sybsun-points has effects on blood pressure and body temperature and pulse rate in humans aged from 20 to 30 who had no specific past history and whose vital signs are in normal range. Methods : 67 persons were studied from March to June 2008. They were composed of Sample group(n=36) and Normal group(n=31). Both two groups kept a steady state an hour before venesection. In both group, we checked blood pressure and body temperature and pulse rates 6 times( 30min. before and just before treatment, and just after, 30, 60, 90min after treatment). All study environments were same between sample and normal group. But only, normal group didn't carry out venesection at the Sybsun-points. Results : In a comparison of before and after venesection at the Sybsun-points, any Statistical significance was not evaluated. Though pulse rate in sample group was significantly decreased after venesection(p<0.05), it has no statistical significance because normal group's pulse rate was also significantly decreased and between two groups had no statistical difference. Conclusions : Though further study is needed, our findings suggest that venesection at the Sybsun-points has no significant effect on blood pressure and body temperature, and pulse rate in humans who had no specific past history and whose vital signs are in normal range. Also in that case, we may know that pain and tension result from venesection at the Sybsun-points have no significant effect on blood pressure and body temperature and pulse rate.

모듈러주택 품질관리를 위한 BIM 적용 방안

이동건,김진원,손정락,Lee, Dong Gun,Kim, Jin Won,Sohn, Jeong Rak 한국토지주택공사 토지주택연구원 2019 LHI journal of land, housing, and urban affairs Vol.10 No.2

The recent paradigm shift in the construction industry has led to a growing demand for industrial construction. In particular, interest in modular housing, one of the areas of industrialization architecture, is soaring. Modular housing is a construction method for completing a building by transporting factory-built modules to the site and assembling them. However, modular housing in Korea has various problems such as errors in design books, lack of factory drawings, and lack of on-site construction plans. BIM is a tool for accumulating, producing and managing various information through 3D models and is a solution to solve various problems of modular housing. In this study, problems of modular housing and BIM utilization of modular housing were presented as ways to ensure the quality of modular housing. Therefore, this study analyzed the problems that are occurring in the construction process of modular housing. And, to address the problem of modular housing, BIM utilization measures were proposed for each modular process step. However, the application of BIM in domestic modular project is currently being carried out in pilot research project. Because of this, the BIM utilize method for modular housing is limited based on the BIM use for general projects and the examples for some modular pilot projects.

VoIP 스니핑을 통한 특정정보 탈취 위험성에 관한 연구

이동건,최웅철,Lee, Donggeon,Choi, Woongchul 디지털산업정보학회 2018 디지털산업정보학회논문지 Vol.14 No.4

Recently, VoIP technology is widely used in our daily life. Even VoIP has become a technology that can be easily accessed from services such as home phone as well as KakaoTalk.[1] Most of these Internet telephones use the RTP protocol. However, there is a vulnerability that the audio data of users can be intercepted through packet sniffing in the RTP protocol. So we want to create a tool to check the security level of a VoIP network using the RTP protocol. To do so, we capture data packet from and to these VoIP networks. For this purpose, we first configure a virtual VoIP network using Raspberry Pi and show the security vulnerability by applying our developed sniffing tool to the VoIP network. We will then analyze the captured packets and extract meaningful information from the analyzed data using the Google Speech API. Finally, we will address the causes of these vulnerabilities and possible solutions to address them.

Klebsiella pneumoniae 표준균주에 대한 Ceftriaxone과 Amikacin의 단독 및 병용요법의 Postantibiotic Effect

이동건,허동호,최정현,유진홍,강문원,신완식,Lee, Dong-Gun,Huh, Dong-Ho,Choi, Jung-Hyun,Yoo, Jin-Hong,Kang, Moon-Won,Shin, Wan-Shik 대한임상약리학회 1999 臨床藥理學會誌 Vol.7 No.1

연구배경 및 방법 : PAE는 세균을 항생제에 제한된 시간 동안 노출시키고 항생제를 제거한 후에도 세균의 성장은 계속 억제되는 현상을 말하며 항생제의 효과는 항생제가 제거된 후에도 일정기간동안 유지되는 것으로 항생제 투여횟수, 시기 등을 결정하는데 중요한 요소로 알려져 있다. 그러나, 항생제와 균의 종류, 농도, 실험조건 둥에 따라 PAE가 다르고 그 길이가 측정하는 방법에 따라 많은 차이가 있다. 특히, 그람음성균에 ${\beta}$-lactam 항생제에 노출되었을 때의 PAE는 정도의 차이가 아닌 그 존재의 유무에 대해서조차 논란이 있는 실정이다. 또한, 그람음성균에 ${\beta}$-lactam과 aminoglycoside를 병용할 때 PAE가 상승작용이 있는지에 대해서도 논란이 있다. 저자들은 K. pneumoniae를 대상으로 ceftriaxone과 amikacin을 병용하였을 때 PAE가 있는지 알아보기 위하여 전통적인 집락수 측정법과 BACTEC 혈액배양법을 사용하고 이를 비교하였고 병용시 상승작용이 있는지 알아보았다. 결 과: (1) K. pneumoniae에 대한 ceftriaxone과 amikacin의 상승작용을 disk diffusion 방법, checkerboard 방법, time-kill curve 및 E-test 등을 이용하여 확인한 결과 무작용의 상관관계를 보였다. (2) 1배 MIC $(0.03\;{\mu}/mL)$의 ceftriaxone에서 집락 수 측정법으로 측정한 PAE는 -0.4시간이었으나, 4배 MIC $(4\;{\mu}/mL)$의 amikacin에서는 2.7시간의 PAE를 나타냈다. (3) 다양한 농도의 ciprofloxacin에 2시간 동안 노출시킨후 집락수 (y)와 BACTEC 혈액배양기의 GV (x)는 log y=0.0514x+4의 관계가 있었으며(r=0.88, p<0.0001), 이를 이용해 ceftriaxone의 PAE를 보정한 결과 0시간으로 정정되었다. (4) ceftriaxone과 amikacin을 병용하였을때 집락수 측정법에 의한 PAE는 3.4시간으로 상가작용을 보였다. 결 론: (1) BACTEC 혈액배양법을 이용한 PAE의 측정결과 K. pneumoniae에 대한 ceftriaxone의 PAE는 집락수 측정법에 의해 과소평가 되어있음이 확인되었고 실제적으로는 PAE를 나타내지 않았다. (2) ceftriaxone이 PAE가 없는 이유는 filament를 형성하기 때문이 아니고 본래 PAE가 없는 것으로 추론된다. Introduction & Methods : The postantibiotic effect (PAE) refers to a suppression of bacterial growth that persists after limited exposure of organisms to antimicrobial agents. The major clinical relevance of the PAE pertains to its impact on antimicrobial dose and dosing interval. There is a method-to-method variation in determination of PAE. In case of Gram negative organisms, ${\beta}$-lactams do not demonstrate PAE on the basis of viable count method, a conventional standard. However, as several Gram negative organisms aggregate to form a filament after exposure to ${\beta}$-lactams, the number of colony may not be precisely counted. To overcome this problem, we also used another indicator of assessing PAE-i.e., growth value which represents $CO_2$ generation from colony. In this study, PAE of ceftriaxone alone and in combination with amikacin were determined for the standard strain of K. pneumoniae using viable counting method and BACTEC blood culture system. Results : (1) Using the disk diffusion method, the checkerboard method, the time kill method and the E-test, we could not find synergistic effects with ceftriaxone and amikacin against K. pneumoniae. (2) On the basis of the viable counting method, PAE of ceftriaxone $({\times}1\;MIC,\;0.03\;{\mu}g/mL)$ was negative (-0.4 hours) and that of amikacin $({\times}4\;MIC,\;4\;{\mu}g/mL)$ was 2.7 hours. (3) Following 2-hour exposure to ciprofloxacin at various concentration, the correlation between the cell count (y) and GV (x) measured by BACTEC blood culture system was significantly high (log y=0.0514x+4, r=0.88, p<0.0001). Although recalculating the PAE of ceftriaxone using the above curve, the subsequently corrected PAE value was 0 hour. (4) The ceftriaxone-amikacin combination caused additive effect for PAE against K. pneumoniae compared with the PAE observed after ceftriaxone or amikacin alone measured by the viable counting method. Discussion : (1) Although it is evident that the viable count method underestimated the PAE of ${\beta}$-lactams agianst K. pneumoniae, PAE was absent in spite of correction by BACTEC blood culture system. (2) It may be possible the ceftriaxone does show no PAE against K. pneumoniae naturally not because of filament formation.