축류송풍기의 저소음 설계에서 수치최적화기법들의 평가

최재호,김광용,Choi, Jae-Ho,Kim, Kwang-Yong 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.10

Three-dimensional flow analysis and numerical optimization methods are presented for the design of an axial-flow fan. Steady, incompressible, three-dimensional Reynolds-averaged Navier-Stokes equations are used as governing equations, and standard k- ${\varepsilon}$ turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Steepest descent method, conjugate gradient method and BFGS method are compared to determine the searching directions. Golden section method and quadratic fit-sectioning method are tested for one dimensional search. Objective function is defined as a ratio of generation rate of the turbulent kinetic energy to pressure head. Two variables concerning sweep angle distribution are selected as the design variables. Performance of the final fan designed by the optimization was tested experimentally.

광결정 Nanocavity를 갖는 InGaN/GaN 양자우물구조의 청색 광소자 공정 및 특성평가

최재호,이정택,김근주,Choi, Jae-Ho,Lee, Jung-Tack,Kim, Keun-Joo 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.12

The authors investigated the InGaN/GaN multi-quantum well blue light emitting devices with the implementation of the photonic crystals fabricated at the top surface of p-GaN layer and the bottom interface of n-GaN layer. The top photonic crystals result in the lattice-dependent photoluminescence spectra at the wavelength of 450 nm and however, the bottom photonic crystal shows a big shift of the photoluminescence peak from 444 nm to 394 nm. The sample with the bottom photonic crystal structure also shows the lasing effect at the wavelength of 468 nm. Furthermore, the quality enhancement for the crystal growth of GaN thin film on the bottom photonic crystal comes from the modulated compressive stress which was measured by the micro-Raman spectroscopy.

모바일 애드혹 네트워크에서 캐쉬 접근 시간 향상을 위한 시간보증 기반의 캐쉬무효화 기법

최재호,오재오,이명수,이상근,Choi, Jae-Ho,Oh, Jae-Oh,Lee, Myong-Soo,Lee, Sang-Keun 한국정보처리학회 2009 정보처리학회논문지 C : 정보통신,정보보안 Vol.16 No.1

모바일 장치의 증가와 무선 네트워크 기술의 발전으로 인해 새롭게 모바일 애드혹 네트워크에 대한 관심이 증가하고 있다. 최근까지의 연구는 데이터 접근성(Accessibility) 향상을 위해 데이터 복사본 활용이 효율적임을 증명하였다. 그러나, 데이터 복사본이 모바일 애드혹 네트워크에서 활용되기 위해서는 원본과 복사본 사이에 일관성(Consistency)이 확보되어야만 한다. 기존의 연구에서 사용되고 있는 일관성 확보 기법은 원본을 가진 노드에게 복사본 사용 노드들이 매번 일관성을 가지는지 확인하는 기법이 활용되었다. 그러나, 시간제약을 가지는 응용의 경우 원본을 가진 노드에게 확인하는 기법은 효율적이지 못하거나 때로는 심각한 문제를 일으킬 수도 있다. 본 논문에서는 시간제약응용을 위한 캐쉬 무효화 기법을 제안하고 있다. 제안하는 기법을 통해 기존의 일관성 확인 기법에서 일어나는 ‘롤백(Rollback)’ 문제를 해결할 수 있었으며, 접근시간(Access time) 측면에서 성능향상을 얻을 수 있었다. 또한 본 논문에서는 임계값 기반의 보완 기법을 제안한다. 우리는 실험 결과를 통해 제안하는 기법이 약간의 현재성(Currency) 손해는 있지만, 접근시간 측면에서 효율적임을 증명하여 준다. Due to the popularity of mobile devices and advances in wireless communication technologies, a mobile ad hoc network has received a lot of attention. In the existing data replication management research, the use of a replica has been shown to be an efficient technique for improving data accessibility. However, to use a replica in ad hoc networks, the data consistency between the original data and the replica should be guaranteed. In the traditional research, a mobile node should check an original data whether the data is updated or not. However, It may be costly or sometimes impossible to check the original data. In the case of the time constraint applications, the checking cost can cause more serious problem. In this paper, we propose the time-guarantee based cache invalidation schemes for time constraint applications and the threshold based compensation method to enhance the time-guarantee based scheme. The proposed schemes can remove the "rollback" problem. Simulation results show that our schemes outperform the previous ones in terms of access time with little loss of data currency.

Erratum : 국가별 마늘의 체질에 따른 면역효능 및 항산화 활성

최재호,정미자,박중현,김형서,오덕환,Choi, Jae-Ho,Chung, Mi Ja,Park, Joong Hyun,Kim, Hyung-Seo,Oh, Deog-Hwan 한국식품위생안전성학회 2016 한국식품위생안전성학회지 Vol.31 No.3

민간발전사업 촉진을 위한 신재생에너지 의무공급량의 비율

최재호,이재헌,Choi, Jae ho,Lee, Jae-Heon 한국플랜트학회 2015 플랜트 저널 Vol.11 No.4

본 논문에서는 2012년 시행된 신재생에너지공급의무화제도(RPS)에 따른 민간발전사들의 RPS 의무이행 현황을 알아보고 신재생에너지 공급인증서의 발급량 부족 및 거래시장에서의 심한 가격변동을 발전사업자들의 RPS 이행시 장애요인으로 분석하였다. RPS시행 이전에 추진하여 최근 준공한 동두천복합발전소에 대한 RPS이행방안 구성결과 연평균 약 334억원의 의무이행비용이 산출되었으며, 해당비용을 당초 사업타당성 검토 기초자료에 반영한 결과 내부수익률이 계획대비 31.8% 저하됨을 알 수 있었다. 신재생에너지 의무공급량의 비율이 해마다 증가하여 2024년부터는 전년도 발전량의 10%를 신재생에너지로 공급해야 하는데 RPS 의무공급 대상자로의 편입 초기부터 10%의 의무공급량을 이행해야 하는 신규 발전소의 경우 의무이행비용 과다로 사업성은 더욱 낮아지므로 의무공급량의 비율을 기존의 12단계에서 17단계로 완화하는 방안을 제시하였다. 즉, 동두천복합발전소의 이행비용을 기준으로 최초 2%부터 매년 0.5%씩 점진적으로 10%까지 높였을 때 내부수익률은 6.23%로써 처음부터 10%의 비율로 공급할 경우 산출한 내부수익률 4.18%보다 약 49%의 사업성 향상 효과를 얻을 수 있어 제도개선이 민간발전사업 촉진에 기여할 것으로 판단된다.

炭化水素內에서의 Alkyl Iodides의 光分解에서 $II^{131}$과 Alkyl Iodides 間의 交換反應

최재호,Choi, Jae-Ho 대한화학회 1966 대한화학회지 Vol.10 No.1

The rate of exchange of I atom between alkyl iodides(ethyl or methyl iodide) and $I_2$ in n-hexane have been determined using $II^{131}$. It is found that the escape of $CH_3$ radicals from a solvent cage is faster than $C_2H_5$ radicals and that photolysis of $C_2H_5I$ is almost identical to that in the case of $CH_3I$.

QR 코드 및 CVS 기반 주소지 자동 기표지 출력 시스템

최재호,정양권,Choi, Jae-Ho,Jeong, Yang-Kwon 한국전자통신학회 2016 한국전자통신학회 논문지 Vol.11 No.1

본 연구는 우편 접수창구에서 고객이 우편물을 보낼 때 마다 사용자의 불편한 문제점을 도출하고, 많은 사용자가 소유하고 있는 휴대전화 단말기에 저장되어 있는 주소 정보를 기반으로 별도의 보안 체계를 별도로 구축하지 않고 우편물의 주소 정보를 우체국 접수창구 단말기(포스 넷)로 주소 정보를 전송하는 방법을 제안하고자 한다. 본 제안 방법은 사용자의 정보를 포스 넷의 2차원 바코드(QR 코드)로 변환한 후 포스 넷에서 QR 코드를 판독하는 방법과 블루투스 등과 같은 근거리 통신망을 이용하여 다량의 주소 정보를 텍스트 화하여 포스 넷에 전송하는 방식이다. 본 제안 방식에 의하여 우편접수시스템과 연동할 경우 모바일용 우편 주소를 자동으로 생성하고 출력해 줄 뿐만 아니라 우편물 접수담당자의 업무를 개선하고, 편리에 따른 경제적 효과를 거둘 수 있었다. This study found that there are problems in sending mails at the postal service reception desks and proposes a system which transmits address information to POSNET(the terminals at post office reception) without the use of an additional security system based on address information which is stored in the terminals of mobile phones. The system proposed transforms the information of users into two-dimensional barcode(QR code) of the POSNET and a number of address information is texturized and transmitted to the POSNET with the use of how to read QR code and LAN such as bluetooth. When the system proposed is connected to the postal reception system, it can create and output mail addresses for mobile computers automatically and contribute to better performance for the post office reception clerks and better economic results.

fMRI를 이용한 망간 노출 용접공의 운동수행에 따른 뇌 활성도 평가

최재호,장봉기,이종화,홍은주,이명주,지동하,Choi, Jae-Ho,Jang, Bong-Ki,Lee, Jong-Wha,Hong, Eun-Ju,Lee, Myeong-Ju,Ji, Dong-Ha 한국환경보건학회 2011 한국환경보건학회지 Vol.37 No.2

Objectives: The purpose of this study is to analyze the effects of chronic exposure by welders to manganese (Mn) through an analysis of the degree of brain activity in different activities such as cognition and motor activities using the neuroimaging technique of functional magnetic resonance imaging (fMRI). The neurotoxic effect that Mn has on the brain was examined as well as changes in the neuro-network in motor areas, and the usefulness of fMRI was evaluated as a tool to determine changes in brain function from occupational exposure to Mn. Methods: A survey was carried out from July 2010 to October 2010 targeting by means of a questionnaire 160 workers from the shipbuilding and other manufacturing industries. Among them, 14 welders with more than ten years of job-related exposure to Mn were recruited on a voluntary basis as an exposure group, and 13 workers from other manufacturing industries with corresponding gender and age were recruited as a control group. A questionnaire survey, a blood test, and an fMRI test were carried out with the study group as target. Results: Of 27 fMRI targets, blood Mn concentration of the exposure group was significantly higher than that of the control group (p<0.001), and Pallidal Index (PI) of the welder group was also significantly higher than that of the control group (p<0.001). As a result of the survey, the score of the exposure group in self-awareness of abnormal nerve symptoms and abnormal musculoskeletal symptoms was higher than those of the control group, and there was a significant difference between the two groups (p<0.05, respectively). In the correlation between PI and the results of blood tests, the correlation coefficient with blood Mn concentration was 0.893, revealing a significant amount of correlation (p<0.001). As for brain activity area within the control group, the right and the left areas of the superior frontal cortex showed significant activity, and the right area of superior parietal cortex, the left area of occipital cortex and cerebellum showed significant activity. Unlike the control group, the exposure group showed significant activity selectively on the right area of premotor cortex, at the center of supplementary motor area, and on the left side of superior temporal cortex. In the comparison of brain activity areas between the two groups, the exposure group showed a significantly higher activation state than did the control group in such areas as the right and the left superior parietal cortex, superior temporal cortex, and cerebellum including superior frontal cortex and the right area of premotor cortex. However, in nowhere did the control group show a more activated area than did the exposure group. Conclusions: Chronic exposure to Mn increased brain activity during implementation of hand motor tasks. In an identical task, activation increased in the premotor cortex, superior temporal cortex, and supplementary motor area. It was also discovered that brain activity increase in the frontal area and occipital area was more pronounced in the exposure group than in the control group. This result suggests that chronic exposure to Mn in the work environment affects brain activation neuro-networks.

국가지정기록물 관리현황과 개선방안 연구

최재호,이영학,Choi, Jae-Ho,Lee, Young-Hak 한국기록학회 2016 기록학연구 Vol.0 No.47

한국근현대사의 굴곡 속에서 공공 및 민간기록물이 훼손되고 유실되었다. 2007년 "공공기관의 기록물관리에 관한 법률"이 "공공기록물관리에 관한법률"로 전면 개정되면서, 민간에 소산되어 있는 주요 기록물을 파악 보존하기 위해 '국가지정기록물'을 지정하는 제도가 보강되었다. 중앙기록물관리기관에서 일정한 기준과 범위를 정하여 '국가지정기록물'을 지정하여 소장기관을 후원함으로서 공공기록물의 한계를 보완하고 한국사회의 역사상을 풍부히 하는데 기여할 것이라 기대하고 만든 제도이다. 2007년부터 2015년까지 총 14건의 기록물이 국가지정기록물로 지정되었다. 본고에서는 어떠한 기록물들이 '국가지정기록물'로 지정되었으며, 소장처들은 국가지정기록물을 어떻게 관리하고 활용해왔는지 살펴보고자 한다. 이를 통해 국가지정기록물 지정제도의 관리현황을 파악하고자 한다. 더불어 '국가지정기록물' 소장기관의 담당자를 면담하여 국가지정기록물 소장처의 기록물 관리현황과 서비스 현황 및 국가지정기록물 지정 효과를 살펴보고, 국가지정기록물 지정제도의 개선방안을 제언하고자 한다. This study is on management present and improvements on National Records Designation System. National Records Designation System is a system that supports management and preservation of changes of records designated by the government through consideration that such records are worth preserving permanently nationally among records acquired by individual or organization. This system is meaningful in a way that it established systematic foundation to hand down by informatizing historic private records which are in danger to be lost or damaged due to lack of proper care. However, compared to the number of designated records, the information that could be practically drawn from such records are limited. This triggered this study to be launched. National Archive sometimes promotes designation and management of National Designated records. Yet archival information service offering access of user to national designated records are very rare. I conducted survey and interview of managers, field research, and documentary research of 10 records holding institution that keeps national designated records currently. I considered that current management status of National Records Designation System can be figured out minutely through these research. As a result of such research, most of the records holding institutions offered display as their least archival information service. The objective of records informatization was to utilize the records. Also further plans on information service related to records and various utilization were suggested. records holding institution manager did not give positive answer on effect of designating national designated records and cooperation between National Archive. Support to National Archive only focused on preservation. For national designated records holding institution designated after 2011 were not getting proper support. In addition, National Archive's support rarely met records holding institution's need. In such circumstances, things to consider for improvements of National Records Designation System is as following. First, designation of national designated records should be based on the utilization of the record. Each records holding institution's willingness to utilize corresponding records and National Archive's ability to draw the willingness out should be considered. Also, it shouldn't be left as mere complementary policy of National Archive's selecting policy. Second, for National Records Designation System to be managed permanently, it should be changed as the system that supports enhancement of private records management. The aim should point to the direction where private can manage and preserve the records on their own. Third, There needs to be changes on the subject and process of national designated records designation. National designated record is the record that was considered valuable by the government among private records. Thus, such records should be the best one to show private field. Accordingly, records that represent contemporary society and include various states and contents should be chosen to be designated. Moreover, public discussion be formed by citizens and related professionals in order to properly select the record.

한약에 의한 소세포성폐암의 퇴축 ; 8년간의 추적조사를 통한 증례보고

최재호,유화승,손창규,조종관,Choi, Jae-Ho,Yoo, Hwa-Seung,Son, Chang-Gue,Cho, Chong-Kwan 대한암한의학회 2005 大韓癌韓醫學會誌 Vol.10 No.1

Objective: It is the aim of the present paper to derive further studies evaluating the effectiveness of oriental medical treatment on SCLC patients. We present a case of SCLC patient who survives over 8 years. Method: We followed all of treatments and examination. We prescribed to the patient what to take HangAmDan (HAD) three times a day. Chest X-ray was performed to evaluate the therapeutic efficacy. Results and conclusion: The patient survives over 8 years. Chest X-rays were shown partial regression. Conclusion: This case may give us a possibility of that oriental medical treatment offers potential benefits for patients with SCLC.