유전 알고리즘을 이용한 최적 공차 설계

장동현,장현수,이병기 한국경영과학회 1998 한국경영과학회 학술대회논문집 Vol.- No.1

The manufacturing industry have made efforts to reduce tolerance size to minimize the reject rate at product design, which causes high costs. When the systematic tolerance design is done, manufacturing cost s should be considered. Therefore, this research analyzes the tolerance within the tolerance design using Monte-Carlo method and sensitivity analysis and using genetic algorithm by tolerance allocation method. The genetic algorithm was developed for allocation of the optimal tolerance under the manufacturing limitation cost.

Lower limb muscle matters in patients with hypoxic brain injury following out-of-hospital cardiac arrest

장동현,Park Seung Min,이동건,김동원,임창우,Jo You Hwan,이귀자 대한중환자의학회 2023 Acute and Critical Care Vol.38 No.1

Background There are conflicting results regarding the association between body mass index and the prognosis of cardiac arrest patients. We investigated the association of the composition and distribution of muscle and fat with neurologic outcomes at hospital discharge in successfully resuscitated out-of-hospital cardiac arrest (OHCA) patients. Methods This prospective, single-centre, observational study involved adult OHCA patients, conducted between April 2019 and June 2021. The ratio of total skeletal muscle, upper limb muscle, lower limb muscle, and total fat to body weight was measured using InBody S10, a bioimpedance analyser, after achieving the return of spontaneous circulation. Restricted cubic spline curves with four knots were used to examine the relationship between total skeletal muscle, upper limb muscle, and lower limb muscle relative to total body weight and neurologic outcome at discharge. Multivariable logistic regression analysis was performed to assess an independent association. Results A total of 66 patients were enrolled in the study. The proportion of total muscle and lower limb muscle positively correlated with the possibility of having a good neurologic outcome. The proportion of lower limb muscle showed an independent association in the multivariable analysis (adjusted odds ratio, 2.29; 95% confidence interval, 1.06–13.98), and its optimal cut-off value calculated through receiver operating characteristic curve analysis was 23.1%, which can predict a good neurological outcome. Conclusions A higher proportion of lower limb muscle to body weight was independently associated with the probability of having a good neurologic outcome in OHCA patients.

차단성 다층 트레이에 포장된 레토르트 닭 가슴살제품의 냉장 중 품질 특성

장동현,이근택,Jang, Dong-Hyun,Lee, Keun-Taik 한국축산식품학회 2012 한국축산식품학회지 Vol.32 No.4

본 연구는 RTE형 레토르트 닭 가슴살을 $10^{\circ}C$에서 24주간 저장하면서 저장 기간에 따른 품질 특성 변화를 확인하고 저장수명을 파악하고자 실시하였다. 미생물은 호기성총균, 중온성 호기성 및 혐기성 포자형성균과 Clostridium spp. 모두 1.0 log CFU/g(검출한계) 이상 검출되지 않았다. pH값은 저장 0일차에 6.56이었고 저장 기간이 길어짐에 따라 감소하는 경향을 보여 저장 24주에 6.34로 나타났다. TBARS값은 최초 0.52 mg MA/kg에서 저장기간이 증가함에 따라 유의적인 경향으로 증가하여 저장 24주에 3.70 mg MA/kg으로 나타났다. VBN값은 저장 초기에 2.1 mg/100 g으로 나타났으며, 저장기간이 길어짐에 따라 유의적으로 점차 증가하여 저장 24주차에 39.9 mg/100 g으로 측정되었다. 포장 내 산소농도는 저장 초기 5.7%에서 저장기간이 길어짐에 따라 점차 감소하여 저장 24주에 3.3%로 나타났다. 저장기간 중 닭 가슴살과 충진액의 황색도는 점차 증가하고, 충진액은 점차 탁해진 것으로 확인되었다. 닭 가슴살의 저장 중 관능적 변화를 살펴 본 결과 저장 24주에 색, 조직감, 이취 및 풍미에 대한 모든 평가항목에서 상품성의 한계치인 5.0 미만으로 측정되었다. RTE형 레토르트 닭 가슴살의 물리화학 및 관능학적 품질 변화 지표들에 대한 결과를 종합해 볼 때 $10^{\circ}C$에서 저장시 최소한 20주간 상품성이 유지될 수 있는 것으로 확인되었다. Ready-to-eat chicken breasts were packaged in a multilayer, gas-tight tray with top film and various quality changes were investigated during the 24 wk of storage at $10^{\circ}C$. Over the storage period, total aerobes, mesophilic aerobic and anaerobic spore formers, and Clostridium spp. were not detected above 1.0 log CFU/g (detection limit). The residual oxygen ratio in the head space of tray and pH values tended to decrease with storage time, namely from initial values of 5.7% and 6.56 to 3.3% and 6.34 at week 24, respectively. Thiobarbituric acid reactive substances and volatile basic nitrogen values increased from 0.52 mg malonaldehyde (MA)/kg and 2.1 mg/100 g initially, to 3.70 mg MA/kg and 39.9 mg/100 g at week 24, respectively. In terms of the change in meat color during storage, the samples showed a slight increasing trend of CIE $a^*$, $b^*$, and ${\Delta}E$ values over the storage period until week 24 (p<0.05). The change in brine color showed a similar trend with meat of which Hunter $b^*$ and ${\Delta}E$ values increased slightly during storage during 24 wk (p<0.05). The values for the transmittance degree of brine in the samples tended to decrease. Moreover, values for the absorbance degree tended to increase with storage time until week 24. The sensory scores for color, texture, odour, and flavour were evaluated below 5.0 (marketability level) after 24 wk of storage. Based on this sensory evaluation, it could be concluded that retorted RTE chicken breast could remain marketable for at least 20 wk at $10^{\circ}C$.

유전 알고리즘을 이용한 최적 공차 설계

장동현,장현수,이병기 대한산업공학회 1998 대한산업공학회 춘계학술대회논문집 Vol.1998 No.4

브로드캐스팅을 고려한 홈네트워킹 시스템

장동현,진용옥 한국어정보학회 2008 한국어정보학 Vol.10 No.1

For the purpose of the Network in the home for multimedia service is one of the solution for delivery, processing, management and reuse of information. Home networking information devices in the home are required connection through wired and wireless network without time and location limitation. Normally, Home network system has been evolved using wired and wireless technologies to meet the technological requirement and installation cost. Home network system should be considered some kind of elements like multi physical layer and protocol support, security of QoS, transmission speed for multimedia service, easy to use at the existing premise and scalability.

[기술해설]자동 요약 시스템

장동현,맹성현 한국정보과학회 1997 정보과학회지 Vol.15 No.10

계획되지 않은 소아응급실 재방문: 환자의 임상적 특성과 응급실 과밀화와의 관련성

장동현,김도균,곽영호,정재윤,서동범,장익완,정재현,서혜향,김주원,추지혜 대한응급의학회 2014 대한응급의학회지 Vol.25 No.5

Purpose: Revisit to the pediatric emergency department(ED) in the short-term period may be due to inadequateevaluation during the previous visit, which may indicate aproblem with quality in emergency care. The aims of thisstudy are to analyze the characteristics of patients whorevisited the pediatric ED within 48 hours after dischargeand to evaluate the relation between overcrowding andrevisit rates. Methods: Retrospectively, we reviewed the charts ofpatients who returned within 48 hours after visiting a PEDduring a one-year period between June 1st, 2011 andDecember 31st, 2011. We determined the rate of return visitsand review the characteristics of patients, emergency severityindex (ESI) level at visits, cause of revisit, diagnosis, andcrowding degree of the pediatric ED at the patient’s first visit. Results: A total of 16,688 patients visited the pediatric EDand 13,716 patients were discharged from the PED duringthe period. Of these discharged patients, 534 patients revisitedinevitably within 48 hours. The most common cause ofrevisit was relapse or worsened symptoms (70.0%). Therewas no significant difference in sex, severity of patient, andcrowding degree of the pediatric ED at the first visit, however,patients who revisited were younger than those who didnot (p=0.005). The ESI level at the return visit was significantlyhigher irrespective of admission after revisit(p<0.001). In diagnosis grouping, patients with gastrointestinaldiseases, respiratory diseases, and neoplastic diseasesshowed a higher rate of revisit. Conclusion: Approximately 4% of our pediatric ED visitswere for children returning within 48 hours. Patients whorevisited were younger and patients with gastrointestinal diseases,neoplastic diseases, and respiratory diseases weremore likely to revisit. Careful explanation of the possibility ofworsened symptoms is necessary for these patients.

기후위기와 생물멸종 그리고 한국교회의 응답

장동현 한신대학교 신학대학원 2020 세계와 선교 Vol.- No.232

기상기후산업 공동활용시스템 활용 및 성과

장동현,김성민,임홍석,이재준,방철한 한국기상학회 2023 한국기상학회 학술대회 논문집 Vol.2023 No.4

인지무선네트워킹 표준을 지원하는개인/휴대기기를 위한 Ecma-International 보안 표준화 현황

장동현,김현성 보안공학연구지원센터 2011 보안공학연구논문지 Vol.8 No.5

최근 들어 기하급수적으로 증가하는 방송 및 통신 시스템으로 인해 무선 주파수 자원의 고갈 문제가 심각하게 대두되고 있다. 이와 같은 주파수 고갈과 비효율적인 주파수 사용 문제를 해결하기 위해 유휴 주파수를 합리적으로 이용하기 위한 인지무선 기술이 많은 관심을 받고 있다. FCC는 스펙트럼 사용 효율을 높이고 새로운 서비스 도입을 용이하게 하기 위해 TV 유휴주파수를 대상으로 주파수 공유기술인 인지무선 기술을 적용하기로 하고 관련 규정을 개정하였다. 이러한 흐름에 맞춰 Ecma-International은 인지무선 기술의 실용화를 위해 개인/휴대기기들을 이용한 인지무선네트워크의 첫 산업표준을 제안하였다. 본 고 에서는 Ecma-International 산업표준을 중심으로 인지무선 기술을 위한 보안 표준화 현황을 살펴본다.