판상형 충전제의 함량과 배향에 따른 PP복합체의 영률 변화 연구

서상범(Sang Bum Seo),이용현(Yong Hyun Lee),정선경(Sun Kyoung Jeong),이승구(Seung Goo Lee),이기윤(Kee Yoon Lee) 한국고분자학회 2012 폴리머 Vol.36 No.2

이 논문은 판상형 충전제의 함량과 배향에 따라 폴리프로필렌 복합체의 영률 변화에 미치는 영향을 연구 하였다. 이론적인 예측은 Lee와 그의 연구자들에 의해 제안된 두 개의 종횡비, ρα=a1/a3과 ρβ=a1/a2 를 이용하여 3차원 타원체의 형상을 계산하였고 실험값과 비교 분석하였다. 판상형 충전제로 운모와 탈크를 사용하였다. 충전제의 형태는 SEM을 이용해 관찰하였고, 종횡비는 고분자의 흐름을 기준으로 좌표축을 설정하여 통계적 방법으로 계 산하였다. 충전제가 운모인 경우에 ρα=13.5와 ρβ=1.8이었고, 탈크의 경우는 ρα=3.8과 ρβ=1.4이었다. 또한 충전제 의 2개의 종횡비와 함량이 기계적 물성에 미치는 영향을 실험적으로 연구하였다. 운모의 경우 30 wt% 함량일 때 E11이 약 2.7배 향상되었다. 탈크의 경우는 E11이 약 2.3배 향상하였다. This paper studied the effects of the content and the orientation of the disk shape fillers on the modulus of PP composites. The experimental results were compared with the theoretical calculations which included the three dimensional ellipsoids and analyzed by two aspect ratios, ρα=a1/a3 and ρβ=a1/a2 proposed by Lee and his researchers. Mica and talc were used as disk shape fillers in the composites. The shapes of mica and talc were observed by SEM and aspect ratios were statistically calculated. For the case of mica, the average aspect ratios were ρα=13.5 and ρβ=1.8, and for the case of talc, they were ρα=3.8 and ρβ=1.4. Also, the effects of two aspect ratios and the content of filler on the mechanical properties were studied: For 30 wt% of mica, E11 increased up to about 2.7 times, and for the other case of talc, E11 increased up to about 2.3 times, respectively.

해외사례 벤치마킹에 기반한 국내 CM 대가체계 개선 시사점 도출

김상범,이정대,김재욱,Kim, Sang-Bum,Lee, Jeong-Dae,Kim, Jae-Wook 한국건설관리학회 2008 건설관리 : 한국건설관리학회 학회지 Vol.9 No.1

국내 CM은 2001년 건설산업기본법에 의해 개념과 범위가 정의된 후 지속적인 성장을 계속해 오고 있다. 하지만, 이러한 CM 제도에 기반한 성장에도 불구하고 국내에서의 CM 적용성과는 기대치에 비해 상대적으로 낮은 것으로 나타났다. 그 주요원인의 하나로 국내 CM제도가 책임감리에 비하여 업무범위가 넓지만, 대가기준은 책임감리에 비해 낮기 때문인 것으로 분석되었다. 따라서, 국내 CM 대가체계의 합리적인 기준을 정립하는 것이 시급할 것으로 판단된다. 본 연구에서는 CM 대가체계의 합리적인 기준을 마련하기 위하여 CMAA, ASCE, DOE, DOL 등의 다양한 해외사례 벤치마킹 연구를 통하여 국내 CM 대가체계를 비교하여 대가 상승요인을 추정하고 대가산정 개선방향을 제시하였다. 분석결과 대가수준은 해외에 비하여 현저하게 낮은 수준인 것으로 판단되었으며, 업무범위는 해외와 비교하여 그 폭이 좁으며 획일적인 구조를 가진 것으로 분석되었다. 따라서, 본 연구에서는 글로벌스탠다드에 따르는 국내 CM 대가체계를 개선하기 위하여 실비정액보수가산(Cost Plus Fixed Fee) 방식을 제시하고, 입 낙찰 전반에 걸친 CM 대가체계에 대한 기준(Framework)을 제시하였다. The Korean Construction Industry significantly contributed to the Korean economic development not only by preparing the domestic infrastructure but also by successfully conducting various international projects. However, major incidents such as the collapse of Sung-Su Bridge and Sam-Pung Department Store along with stagnation of Korean Economy have raised questions about underlying systematic problems of the Korean Construction Industry. As a solution to resurrect the Korean Construction Industry, the Construction Management (CM) system introduced in late 1990's and increasingly utilized as an innovative delivery system. Despite of the fast growth of CM, the performance of CM has not been up to the hype and low CM fee has been identified as one of the main reasons of unsatisfactory CM performance. Therefore, this research attempted to propose ways of improving 'CM Fee Guidelines' published by Korean Ministry of Construction and Transportation by conducting a benchmarking study on Global Standards of estimating CM Fee. International organizations benchmarked in this research include CMAA, ASCE, DOL, DOE, etc. Various investigation and analysis revealed that Korean 'CM Fee Guidelines' need to significantly modified comparing to Global Standards. This research also tried to prepare recommendations to improve the CM deliver system focusing on the 'Method of CM Fee Estimation' and Selection of a CM firm as an owner's agent.

Situating Artificial Intelligence: The Convergence of Human Emotion and Technology in Cyberpunk SF Films

( Sung Bum Lee ) 한국영미문화학회 2015 영미문화 Vol.15 No.1

Researchers of artificial intelligence (shortly AI) question digital-binary technology to set up human-compatible technology. Since current digitized AI machinery tends to simulate abstract human intelligence, it cannot be context-sensitive. Human-compatible search models such as genetic algorithm and neural network, however, overcome the de-contextualization of digital simulation. Running counter to contextless, digital-binary, sequential procedure, they pursue contextual, bidirectional algorithm. Simply put, digital AI technology seeks a top-down, pre-set computation, whereas human-compatible AI technology aspires for a bottom-up, situation-specific computation. Acting against the de-contextualization of artificial intelligence, emotion technology is a crucial part of human-adaptable technology. For computing human inner experiences lies at the peak of the contextualization of AI technology. Affective technology maximizes a bottom-up, situation-specific computation. In my essay I approach it in light of the convergence of literature and technology. The opposition between digital AI technology and affective AI technology replays itself through the conflict between artificial intelligence and artificial feeling in cyberpunk SF movies. They explore the tension of the contextless simulation of human intelligence and situation-specific simulation of human emotion. I compare Bicentennial Man, A.I., and Terminator: Salvation with the Matrix trilogy. While the former prioritizes human complex feelings over abstract mechanic intelligence, the latter treats human emotion as a new kind of programming although being distinct from digital computing. The Matrix series do not pursue human emotion as a prerogative of humanity. Instead, the films draw parallels between human inner qualities and systemic instabilities in the Matrix. Precisely, the Matrix``s control of Neo’s affective involvements such as free will and love is the anthropocentric counterpart of autonomous variations in a system. The Matrix trilogy thematizes the artificial re-creation of human emotion itself instead of sanctifying it unconditionally. Accordingly, the Matrix trilogy displays the interdisciplinary convergence of the humanities and technology. I argue that the gradual popularity of affective technology implicates the individualization of technological control.

A Design of Navigation System Using Stratospheric Airships in South Korea

Lee, Eun-Sung,Chun, Se-Bum,Lee, Young-Jae,Hur, Jung,Kang, Tae-Sam The Korean Society for Aeronautical and Space Scie 2006 International Journal of Aeronautical and Space Sc Vol.7 No.2

For a relatively small country like Korea, a radionavigation system using airships can be considered, which is to provide the navigation service utilizing the stratospheric airships that are deployed in the stratosphere at the altitude of around 20-23km, and which is an independent or a back-up radionavigation system other than current GPS or GLONASS. In this paper, a feasibility study on the constellation of stratospheric airships for the navigation system has been performed. A measure of a geometrical condition between a receiver and navigation transmitters. called the DOP (Dilution of Precision), determines the resulting positioning error of the navigation system, if the error of range measurement is predictable. Therefore, with assumption that the range measurement error of the stratospheric airship navigation system is quite similar to GPS. the several DOP values have been used to evaluate the performance of the navigation system with comparing with the DOP values of GPS as the reference values. To provide the position information of the navigation transmitters to users, a receiver cluster system fixed on the ground, called an IGPS (inverted GPS), is proposed, and the error is also evaluated using the DOP values. Five areas around five major cities in South Korea have been selected, and then by numerical simulations the DOP values are compared those of GPS to assess the performance of the proposed navigation system using stratospheric airships. The possible frequency bands have been proposed. and then link budget of the navigation transmitter has been analyzed for the proposed navigation system.

Selecting Fuzzy Rules of Pattern Classification Systems

Sang-Bum Lee,Sung-joo Lee,Mal-Rey Lee 한국지능시스템학회 2002 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.2 No.2

Salt and pepper appearance of the skin associated with mixed connective tissue disease

( Sang-hyeon Won ),( Woo-il Kim ),( Min-young Yang ),( Won-ku Lee ),( Tae-wook Kim ),( Sung-min Park ),( Hyun-joo Lee ),( Gun-wook Kim ),( Hoon-soo Kim ),( Hyun-chang Ko ),( Byung-soo Kim ),( Moon-bum 대한피부과학회 2018 대한피부과학회 학술발표대회집 Vol.70 No.1

The salt-and-pepper appearance of skin is composed of salt (vitiligo-like depigmentation) and pepper(perifollicular pigmentation). This characteristic feature can be a clinical clue for the diagnosis of systemic sclerosis. Mixed connective tissue disease(MCTD) is a distinct disease entity with mixed features of systemic lupus erythematosus, systemic sclerosis, myositis and rheumatoid arthritis with high titers of antibodies to U1 small nuclear ribonucleoprotein(U1 snRNP). Therefore, MCTD is known to have a wide spectrum of cutaneous manifestations which may be the presenting signs of the disease. However, there are few reports of pigmentary changes in MCTD. A 51-year old woman presented with variably sized hypopigmented macules along with relative hyperpigmentation of the perifollicular areas. She was diagnosed with MCTD by Raynaud’s phenomenon and high titer anti-RNP corresponding to a speckled antinuclear antibody of 1:1280 in Rheumatology clinic. A biopsy specimen showed dermal sclerosis. Pigment loss and melanophages were observed in the papillary dermis. Hypo- and hyperpigmentation were confirmed histologically by S100 and Fontana-Masson stain. To our knowledge, ‘salt and pepper appearance of the skin’ has rarely been reported in MCTD. The diagnosis of MCTD can be challenging due to its diverse characteristics. Therefore, we suggest that MCTD should be regarded as a differential diagnosis in patient with this pigmentary change.

Association among Working Hours, Occupational Stress, and Presenteeism among Wage Workers

Sung-Hwan Jeon,Jong-Han Leem,Shin-Goo Park,Yong-Seok Heo,Bum-Joon Lee,So-Hyun Moon,Dal-Young Jung,Hwan-Cheol Kim 대한직업환경의학회 2014 대한직업환경의학회지 Vol.26 No.-

Objectives: The purpose of the present study was to identify the association between presenteeism and long working hours, shiftwork, and occupational stress using representative national survey data on Korean workers. Methods: We analyzed data from the second Korean Working Conditions Survey (KWCS), which was conducted in 2010, in which a total of 6,220 wage workers were analyzed. The study population included the economically active population aged above 15 years, and living in the Republic of Korea. We used the chi-squared test and multivariate logistic regression to test the statistical association between presenteeism and working hours, shiftwork, and occupational stress. Results: Approximately 19% of the workers experienced presenteeism during the previous 12 months. Women had higher rates of presenteeism than men. We found a statistically significant dose?response relationship between working hours and presenteeism. Shift workers had a slightly higher rate of presenteeism than non-shift workers, but the difference was not statistically significant. Occupational stress, such as high job demand, lack of rewards, and inadequate social support, had a significant association with presenteeism. Conclusions: The present study suggests that long working hours and occupational stress are significantly related to presenteeism.

Si 도핑이 InAs 자기조립 양자점 적외선 소자 특성에 미치는 효과

서동범,황제환,오보람,김준오,이상준,김의태,Seo, Dong-Bum,Hwang, Je-hwan,Oh, Boram,Kim, Jun Oh,Lee, Sang Jun,Kim, Eui-Tae 한국재료학회 2019 한국재료학회지 Vol.29 No.9

We investigate the characteristics of self-assembled quantum dot infrared photodetectors(QDIPs) based on doping level. Two kinds of QDIP samples are prepared using molecular beam epitaxy : $n^+-i(QD)-n^+$ QDIP with undoped quantum dot(QD) active region and $n^+-n^-(QD)-n^+$ QDIP containing Si direct doped QDs. InAs QDIPs were grown on semi-insulating GaAs (100) wafers by molecular-beam epitaxy. Both top and bottom contact GaAs layer are Si doped at $2{\times}10^{18}/cm^3$. The QD layers are grown by two-monolayer of InAs deposition and capped by InGaAs layer. For the $n^+-n^-(QD)-n^+$ structure, Si dopant is directly doped in InAs QD at $2{\times}10^{17}/cm^3$. Undoped and doped QDIPs show a photoresponse peak at about $8.3{\mu}m$, ranging from $6{\sim}10{\mu}m$ at 10 K. The intensity of the doped QDIP photoresponse is higher than that of the undoped QDIP on same temperature. Undoped QDIP yields a photoresponse of up to 50 K, whereas doped QDIP has a response of up to 30 K only. This result suggests that the doping level of QDs should be appropriately determined by compromising between photoresponsivity and operating temperature.

Accumulation of 99mTc - Methylene Diphosphonate in a healing Surgical Wound

Lee, Dong Soo,Chung, June Key,Kim, Sang Eun,Lee, Myung Chul,Koh, Chang Soon,Lee, Bum Woo,Kim, Deog Yoon 대한핵의학회 1990 핵의학 분자영상 Vol.24 No.1

Dominance of Plasmonic Resonant Energy Transfer over Direct Electron Transfer in Substantially Enhanced Water Oxidation Activity of BiVO₄ by Shape-Controlled Au Nanoparticles

Lee, Mi Gyoung,Moon, Cheon Woo,Park, Hoonkee,Sohn, Woonbae,Kang, Sung Bum,Lee, Sanghan,Choi, Kyoung Jin,Jang, Ho Won Wiley Blackwell (John Wiley Sons) 2017 Small Vol.13 No.37