기후정보를 반영한 확률적 일정계획수립 모델 개발

박재현,김경훈,김재준,Park, Jae-Hyun,Kim, Kyong-Hoon,Kim, Jae-Jun 대한건축학회 2011 대한건축학회논문집 Vol.27 No.2

This study aims to overcome problems of scheduling established by planner's institution and judgment. By introducing stochastic approach, this study proposes a method to predict work duration on the construction sites reflecting work information generated around unit work of previous cases and non-working day, and this model was verified by its application to a case study. As a result of analyses on previous researches in an attempt to develop work duration model, there were several studies on estimating work duration based on stochastic approach. However, previous researches could not predict work duration in different construction sites because unit work was not separated. Accordingly, this study attempts to suggest a practical method to predict work duration in advance in pre-construction phase where construction is not under way. After predicting construction time of a site where duration is supposed to be predicted based on the data of measuring case study, verification of this model was carried out in compared to real construction time. In consequence, work duration within twelve days was been estimated with a margin of error of 5%. In addition, the period for actual construction turned out ten days, which was analyzed within twelve day. Therefore, model of this study show the practical method estimating work duration in pre-construction phase.

작업자의 작업공구에 따른 근골격계 질환과 작업효율 모델

박재현,김경훈,김재준,Park, Jae-Hyun,Kim, Kyong-Hoon,Kim, Jae-Jun 대한건축학회 2011 대한건축학회논문집 Vol.27 No.2

Due to a massive outbreak in the workplace and a rapid increase of industrial disaster victims, musculoskeletal disorders is recently emerging as a major issue in the field of industry safety and health. Musculoskeletal disorders has already held a high rank of occupational diseases in advanced countries and it is rapidly growing every year in Korea. In particular, it is expected that people working in the construction industry have higher rates of musculoskeletal disorders given that the construction industry requires a higher level of dependence on human labor and laborers' high intensity of physical labor outside. In this regard, targeting laborers involving in building construction, this study attempts to analyze the impact of musculoskeletal disorders which can be shown according to working hand tools, making to model musculoskeletal disorders on efficiency. As a result of analyses, it appears that there are differences in body parts that hurt skeleton and musculature between structural steel laborers and carpenters owing to different working hand tools they use. In case of structural steel laborers, they tend to feel most psychological distress when their necks and shoulders are under stress. In contrast, carpenter is likely to be agitated when their legs and knees are exposed to stress. Accordingly, this study is worthwhile by finding out different levels of musculoskeletal stress and different body parts depending on the tools laborers use, in turn proving that this has an impact on efficiency through modeling and quantifying it.

북한산국립공원의 계류수질 보전 전략(I)

박재현,우보명,김우룡,안현철,조현서,추갑철,김춘식,최형태,Park, Jae-Hyeon,Woo, Bo-Myeong,Kim, Oue-Ryong,Ahn, Hyun-Chul,Cho, Hyun-Seo,Choo, Gab-Chul,Kim, Choon-Sig,Choi, Hyung-Tae 한국환경복원기술학회 2001 한국환경복원기술학회지 Vol.4 No.3

This study was conducted to investigate physicochemical property changes from July 1998 to August 2001 in Mt. Bukhansan National Park. Four water sampling points were selected to measure the quality of stream water in the northeastern part of the Mt. Bukhansan National Park. The results were summarized as follows; In spring, the average pH of stream water was below the first class of the river water quality standard, while it was normal level in summer. The average electrical conductivity was about 2.3~3.3 times higher in downstream water than in upstream water during spring and summer. The contents of anions($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$) were about 1.1~7.4 and 0.4~11.4 times higher in downstream than in upstream water, respectively. These results indicate that water quality was poorer in downstream than in upstream water. We suggest that stream water in the Mt. Bukhansan National Park should be protected from impacts of snow melting mineral particles in spring season and human impacts like wastewater of point source in summer season.

수도권 국도교량 세굴위험도 평가 및 등급화 사례 연구

박재현,김정훈,안성철,이주형,정문경,곽기석,Park,Jae-Hyun,Kim,Jeong-Hun,An,Seong-Chul,Lee,Ju-Hyung,Chung,Moon-Kyung,Kwak,Ki-Seok 한국방재학회 2008 한국방재학회논문집 Vol.8 No.2

홍수 시 세굴로 인한 교량 기초의 파괴는 국내외적으로 교량 붕괴의 첫 번째 원인이다. 본 연구에서는 수도권 지역의 실제 국도교량에 대하여 세굴 위험도 평가 및 등급화를 수행하였다. 30개소 교량을 선정하여 지반 시추조사를 포함한 현장조사, 설계 홍수량에 대한 교량세굴 해석, 그에 따른 교량기초의 지지력 평가 및 위험도 분석을 하였고, 이를 바탕으로 교량세굴 위험도를 등급화 하였다. 위험도 평가 결과 직접확대기초 교량 26개소 중 9개소 교량이 장래 세굴 위험 가능성이 있는 것으로 나타났고, 나머지 17개소 교량은 안정한 수준으로 나타났다 말뚝기초 교량 4개소 중 3개소의 교량이 유의할 만한 수준으로 지지력이 감소하는 것으로 평가되었다. Foundation failure due to bridge scour during floods is the leading cause of bridge failure. Performed were the evaluation of bridge scour vulnerability and prioritization on real bridges registered in the National Highway Bridge Inventory of the capital region. The case studies for 30 national highway bridges consist of site investigation including boring test, bridge scour analysis fur the design flood, bearing capacity evaluation of the bridge foundation before and after scour, comprehensive evaluation of bridge scour vulnerability, and prioritization. Nine of 26 spread (feting bridges showed the potential future vulnerability to scour with significant decrease in the bearing capacity of foundations due to scour and the remaining 17 spread footing bridges were expected to maintain their stability to resist the effects of scour. Three of 4 pile foundation bridges exhibited considerable decrease in the bearing capacity of foundation after scour.

당뇨병 환자에서 관절경적 회전근 개 봉합술 후 발생한 화농성 견관절염의 치료 - 증례 보고 -

박재현,최원기,김세식,최창혁,Park, Jae-Hyun,Choi, Won-Ki,Kim, Se-Sik,Choi, Chang-Hyuk 대한관절경학회 2009 대한관절경학회지 Vol.13 No.1

Two diabetes mellitus patients treated by arthroscopy and associated procedure for an infection after arthroscopic rotator cuff repair were involved. The time interval from rotator cuff repair to symptom development was 18 days in average and arthroscopic debridement and associated procedure for infection applied in average 65 days after symptom development. Patient evaluation was done according to the KSS, ASES, UCLA and Constant Score. We used antibiotics for average 22.5 days after arthroscopic debridement and associated procedure, the infection was treated in average 4 months. At final follow-up, the mean KSS score was 82 points, the mean UCLA score was 33 points, the mean ASES score was 91 points, the mean Constant score was 71 points. All infections following arthroscopic rotator cuff repair were cured by arthroscopy and associated procedure. ROM and functional results were much improved, the pain and satisfaction were also much improved.

Al₂O₃와 TiO₂의 반응소결로 제조한 Al₂TiO₅-기계가공성 세라믹스

박재현,이원재,김일수,Park, Jae-Hyun,Lee, Won-Jae,Kim, Il-Soo 한국세라믹학회 2010 한국세라믹학회지 Vol.47 No.6

Aluminium titanate($Al_2TiO_5$) has extremely anisotropic thermal expansion properties in single crystals, and polycrystalline material spontaneously microcracks in the cooling step after sintering process. These fine intergranular cracks limit the strength of the material, but provide an effective mechanism for absorbing strain energy during thermal shock and preventing catastrophic crack propagation. Furthermore, since machinable BN-ceramics used as an insulating substrate in current micro-electronic industry are very expensive, the development of new low-cost machinable substrate ceramics are consistently required. Therefore, cheap $Al_2TiO_5$-machinable ceramics was studied for the replacement of BN ceramics. $Al_2O_3-Al_2TiO_5$ ceramic composite was fabricated via in-situ reaction sintering. $Al_2O_3$ and $TiO_2$ powders were mixed with various mol-ratio and sintered at 1400 to $1600^{\circ}C$ for 1 h. Density, hardness and strength of sintered ceramics were systematically measured. Phase analysis and microstructures were observed by XRD and SEM, respectively. Machinability of each specimens was tested by micro-hole machining. The results of research showed that the $Al_2TiO_5$-composites could be used for low-cost machinable ceramics.

소아 IgA 신병증의 예후에 관한 고찰

박재현,김병길,정현주,최인준,Park Jae-Hyun,Kim Pyung-Kil,Jeong Hyeon-Joo,Choi In-Joon 대한소아신장학회 1997 Childhood kidney diseases Vol.1 No.1

After the first description of IgA nephropathy by Berger in 1968, the prognosis of this disease was considered favourable. However recent studies have revealed that IgA nephropathy result in end stage renal desease in 25-30% by 20 years. Heavy proteinuria, hypertension, histological high class are regarded as poor prognostic factors. In 1996, Yagame et al reported the new histopathologic grading with a strong correlation between the grading, heavy proteinuria, high s-Cr level and renal survival. The aims of this study are to determine whether the pathological grading and other clinical parameters could contribute to predicting the outcome of this disease eventhough pediatric patients. Seventy nine patients (59 males, 20 females) with IgA nephropathy were examined. Patients were 2.08-15.17 years of age ($9.85{\pm}2.83$). The mean follow-up duration were $27{\pm}28$ months. Six of seventy nine patients progressed to chronic renal failure during the follow-up periods. High 24h urinary protein excretion at diagnosis were significantly higher in chronic renal failure patients (p<0.05). Hypertension at diagnosis were the significant associated factors in progression of chronic renal failure (p<0.05). Histological changes of IgA nephropathy in light microscopy were classified into five classes by WHO classification, four grades in Yagame's gradings. Among the seventy nine patients, 24 were as class 1, 30 as class 2, 23 as class 3; 4 as class 4, 0 as class 5 by WHO classification. 23 were classified grade 1, 31 as grade 2, 24 as grade 3, 1 as grade 4 by Yagame's grading. Among six patients who progressed to chronic renal failure, 1 clssified as class 1, 1 as class 2, 3 as class 3, 1 as class 4, 0 as class 5 by WHO Classification. 1 patients were classified as grade 1, 1 as grade 2, 3 as grade 3, 1 as grade 4 by Yagame's grading. (p>0.05) In conclusion, hypertension and heavy proteinuria at initial presentation were significantly associated with progression of chronic renal failure. The classification of WHO & Yagame's grading has no significant association with the progression of chronic renal failure in pediatric patients.

백운산 지역에서 계류수의 이화학적 성질에 미치는 양어장의 영향(II)

박재현,우보명,김우룡,안현철,Park, Jae-Hyeon,Woo, Bo-Myeong,Kim, Oue-Ryong,Ahn, Hyun-Chul 한국환경복원기술학회 2001 한국환경복원기술학회지 Vol.4 No.1

Quantifications of fish farm influences on stream water quality may provide basic informations on watershed management to reduce environmental impact due to fish farm development and to conserve stream water quality in forested watershed area. In this research stream water qualities around Mt. Paekun area were monitored seasonally and the following results were obtained. Due to the increase of pH in effluent water from the fish farm it was believed that alkalization of stream water can be accelerated by large scale development of fish farms in the forested watershed area. Negative effects on stream water quality were observed by indications of increase in electrical conductivity and temperature of effluent water from the fish farm. Decreases in physicochemical indices such as the amount of dissolved oxygen, percentage of dissolved oxygen, total amount of cation, total amount of anion and total amount of ion in effluent water from the fish farm were also negative aspects in downstream ecology. It is recommended that water purification system as well as eco-friendly fish farm design should be incorporated to large scale fish farm development plan in forested watershed area.

적취(積聚)를 위주로 종양(腫瘍)의 병인병기(病因病機)에 관한 소고(小考)

박재현,엄석기,정현식,김경석,윤성우,최원철,Park, Jae-Hyun,Eum, Seok-Ki,Cheong, Hyun-Sik,Kim, Kyung-Seok,Yun, Seong-Woo,Choi, Won-Cheol 대한암한의학회 2007 大韓癌韓醫學會誌 Vol.12 No.1

Homocysteine과 혈중(血中) 지질농도(脂質濃度)와의 상관성(相關性) 연구(硏究)

박재현,황우준,조남근,김성철,고영철,Park, Jae-Hyun,Hwang, Woo-Jun,Cho, Nam-Geun,Kim, Sung-Chul,Ko, Young-Chul 대한한방내과학회 2006 대한한방내과학회지 Vol.27 No.3

Object : This study was carried out to investigate the correlation between homocysteine and serum lipids which are known risk factors of stroke. Methods : The subjects were a total of 60 patients divided into a control group (n =30) and a sample group (n =30). The control group was normal homocysteine level without clinical symptoms, and the sample group was high homocysteine level with headache, dizziness, hypertension and so on. clinical symptoms, Each group was measured and compared for serum homocysteine, total cholesterol, triglyceride(TG), low density lipoprotein(LDL), and high density lipoprotein(HDL). Results : Total cholesterol, TG, and LDL were significantly increased and HDL was significantly decreased in the sample group. which was a high homocysteine level group compared with the control group, which was a normal homocysteine level group. Conclusion : In these results. it was suggested that increase of homocysteine leads to increase of serum total cholesterol, TG, LDL, but causes decrease of HDL. It seemed that risk of stroke is more at high homocysteine level than normal.