• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.3
• /
• pp.314-322
• /
• 2008

This study was carried out to assess aerobic stabilized waste sludge as liquid fertilizer for the growth of cucumber, cabbage and chrysanthemum. Sludge was pretreated with NaOH(40 meq/L) at 40$^{\circ}C$ for 330 min. The number of fecal coliforms in batch test sludge fertilizer was more efficiently reduced than those in continuous one, maybe due to longer SRT. All produced fertilizer belonged to class B according to US EPA requirement at least. Among 6 heavy metals regulated in Korea, As, Cd and Hg were not detectable in plant amended with fertilizer whereas the concentration of Cr, Cu and Pb in plant was less than 10 mg/kg dw. However, Zn and Ni, which were restricted in other country, but not in Korea, were detected in most amount of 118 mg/kg and 15.7 mg/kg, respectively. Furthermore, based on dry weight of plant, digested sludge(5.4 mg, dw) functioned as better fertilizer rather than activated sludge (4.3 mg, dw), much more fertile when those sludge was pretreated(1.24 mg, dw) compared to untreated one(1.12 mg, dw). But its fertility was 60$\sim$80% of commercial fertilizer and accumulation of Zn, Ti and Cr in plant was founded. Therefore, it could be concluded that sludge-fertilizer can be used for flower unlimitedly, but for edible plant limitedly as additive fertilizer.

• Journal of Life Science
• /
• v.26 no.1
• /
• pp.129-139
• /
• 2016

Exercise increases the expression and interaction of major neurotrophic factors such as brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF) at both central and peripheral tissues, which contributes to improved brain and neural plasticity and cognitive function. Previous findings have been to understand the effect of light or moderate intensity aerobic exercise on neurotrophic factors and cognitive function, not that of high intensity aerobic exercise. However, recent findings suggest that high intensity interval training is a safe, less time-consuming, efficient way to improve cardiorespiratory fitness and weight control, thus American College of Sport Medicine (ACSM)’s guidelines for exercise prescription for various adult populations also recommend the application of high intensity interval training to promote their overall health. High intensity interval training also enhances the expression of BDNF, IGF-1, and VEGF at the brain and peripheral tissues, which improves cognitive function. Increased frequency of intermittent hypoxia and increased usage of lactate as a supplementary metabolic resource at the brain and neural components are considered a putative physiological mechanism by which high intensity interval training improves neurotrophic factors and cognitive function. Therefore, future studies are required to understand how increased hypoxia and lactate usage leads to the improvement of neurotrophic factors and what the related biological mechanisms are. In addition, by comparing with the iso-caloric moderate continuous exercise, the superiority of high intensity interval training on the expression of neurotrophic factors and cognitive function should be demonstrated by associated future studies.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.5
• /
• pp.681-688
• /
• 2022

According to a recent study, most construction companies in Korea do not manage risk effectively, and it is judged that the risk management system needs to be improved. In addition, most risk-related studies deal with risks from a macroscopic perspective, and there are few studies dealing with process risks at the project construction stage. Therefore, this study tried to suggest a risk response plan through analysis and classification of risk factors that may occur in retaining work among process risks. To this end, a workshop was held for risk experts to identify and analyze risks that may occur during the construction of retaining work for apartments. As a result of the study, it was expected that savings of KRW 4.97 billion would be possible in the 95 % confidence interval, and the maximum possible cost was reduced from KRW 15 billion to about KRW 10 billion. Based on the risk reduction ratio, it was found that risks that can be reduced without any special input cost, risks with large effects in response to risks, and risks with insignificant effects were found. Therefore, using the types and risk factors presented in this study as guides, it is expected that it will be helpful in successfully operating the project if an appropriate response strategy is prepared and systematically responded to the site conditions.

• Korean Journal of Plant Resources
• /
• v.9 no.2
• /
• pp.197-201
• /
• 1996

To greatly decrease bolting rate and deterioration of root quality, seeds of Angelica gigas had sown and grown several month earlier than traditional seedtime. Roots were harvested in the middle of November in same year. Roots were devided to several parts such a fune root, secondary root, stele and cortex of main root. We ditermined and compared with the major constisuents contained in each parts of 1 and 2 year old roots. Among each parts of root, the amount of constituents in the fine root and cortex were much higher than those in stele of main root. Content of decursin and decursinol angelate was higher 6.5% in 2 year old root than 4.8% in 1 year old root and their component ratio showed 10:7.5 in 1 year old root and 10:6.0 in 2 year old root, respectively. But merits as a material of oriental medicine for 1 year old root that cultivated by early short-time growing seedling were generally acknowledged.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.2
• /
• pp.191-196
• /
• 2010

Hybrid heat pumps, which combine the vapor compression and absorption heat pump cycle, can efficiently produce hot water of $80^{\circ}-90^{\circ}C$ from the low temperature of ${\sim}50^{\circ}C$. In this study, the performance of a two-stage hybrid heat pump (HHP) was compared with a single-stage hybrid heat pump using EES (Engineering Equation Solver). For the same operating conditions, the two-stage HHP showed a slightly higher COP (Coefficient Of Performance) and more stable operating conditions than the single-stage HHP. Moreover, the maximum working fluid temperature of the two-stage HHP was found to be lower than that of the single-stage HHP by about 40 K, which makes the working conditions of the lubricating oil safer. The COPs of both systems decreased with increasing UA-values. However, the heat output of the HHP was increased at the same time.

• Proceedings of the Korean Society of Computational and Applied Mathematics Conference
• /
• 2003.09a
• /
• pp.11-11
• /
• 2003

오늘날 단일 슈퍼컴퓨터로는 처리가 불가능한 거대한 문제들의 해법이 시도되고 있는데, 이들은 지리적으로 분산된 슈퍼컴퓨터, 데이터베이스, 과학장비 및 디스플레이 장치 등을 초고속 통신망으로 연결한 GRID 환경에서 효과적으로 실행시킬 수 있다. GRID는 1990년대 중반 과학 및 공학용 분산 컴퓨팅의 연구 과정에서 등장한 것으로, 점차 응용분야가 넓어지고 있다. 그러나 GRID 같은 분산 환경은 기존의 단일 병렬 시스템과는 많은 점에서 다르며 이전의 기술들을 그대로 적용하기에는 무리가 있다. 기존 병렬 시스템에서는 주로 동기 알고리즘(synchronous algorithm)이 사용되는데, 직렬 연산과 같은 결과를 얻기 위해 동기화(synchronization)가 필요하며, 부하 균형이 필수적이다. 그러나 부하 균형은 이질 클러스터(heterogeneous cluster)처럼 프로세서들의 성능이 서로 다르거나, 지리적으로 분산된 계산자원을 사용하는 GRID 환경에서는 이기종의 문제뿐 아니라 네트워크를 통한 메시지의 전송 지연 등으로 유휴시간이 길어질 수밖에 없다. 이처럼 동기화의 필요성에 의한 연산의 지연을 해결하는 하나의 방안으로 비동기 반복법(asynchronous iteration)이 나왔으며, 지금도 활발히 연구되고 있다. 이는 알고리즘의 동기점을 가능한 한 제거함으로써 빠른 프로세서의 유휴 시간을 줄이는 것이 목적이다. 즉 비동기 알고리즘에서는, 각 프로세서는 다른 프로세서로부터 갱신된 데이터가 올 때까지 기다리지 않고 계속 다음 작업을 수행해 나간다. 따라서 동시에 갱신된 데이터를 교환한 후 다음 단계로 진행하는 동기 알고리즘에 비해, 미처 갱신되지 않은 데이터를 사용하는 경우가 많으므로 전체적으로는 연산량 대비의 수렴 속도는 느릴 수 있다 그러나 각 프로세서는 거의 유휴 시간이 없이 연산을 수행하므로 wall clock time은 동기 알고리즘보다 적게 걸리며, 때로는 50%까지 빠른 결과도 보고되고 있다 그러나 현재까지의 연구는 모두 어떤 수렴조건을 만족하는 선형 시스템의 해법에 국한되어 있으며 비교적 구현하기 쉬운 공유 메모리 시스템에서의 연구만 보고되어 있다. 본 연구에서는 행렬의 주요 고유쌍을 구하는 데 있어 비동기 반복법의 적용 가능성을 타진하기 위해 우선 이론적으로 단순한 멱승법을 사용하여 실험하였고 그 결과 순수한 비동기 반복법은 수렴하기 어렵다는 결론을 얻었다 그리하여 동기 알고리즘에 비동기적 요소를 추가한 혼합 병렬 알고리즘을 제안하고, MPI(Message Passing Interface)를 사용하여 수원대학교의 Hydra cluster에서 구현하였다. 그 결과 특정 노드의 성능이 다른 것에 비해 현저하게 떨어질 때 전체적인 알고리즘의 수렴 속도가 떨어지는 것을 상당히 완화할 수 있음이 밝혀졌다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.26 no.5
• /
• pp.519-527
• /
• 2008

The basic elements in precise geoid determination are the gravity and topographic data with reliable quality and distribution. In this study, the effect of the gravity and topographic data on the precision of the geoid are analyzed through simulations in which the quality and distribution of the data are artificially controlled. It was found that the distribution of the topographic data has more effect on the precision of geoid than the quality of the it. This leads to the conclusion that the SRTM (Shuttle Radar Topography Mission) DTM (Digital Terrain Model) with resolution of 90m is qualified as a topographic data in geoid determination. In the experiments with gravity data, on the other hand, the aliasing effect caused by the low data density caused large errors in geoid. It was found that the more gravity data especially in north-eastern mountainous area is needed for precise geoid determination in Korea.

• Journal of Korean Society of Transportation
• /
• v.20 no.3
• /
• pp.179-192
• /
• 2002

주차금지, 일방통행. 본 논문에서의 횡단보도와 같은 교통표지는 개별적 행위로서 행정행위가 아니라 불특정 다수의 행위를 추상적으로 규율하는 특성을 지닌다. 현행 도로교통법상 횡단보도의 설치여부는 지방경찰청장의 재량 사항으로 규정되어 있어 경찰이 횡단보도를 새로 설치하거나 기존의 횡단보도를 폐지하는 경우 관할 경찰청은 물론 관계 행정청에 이를 설치 혹은 폐지해달라는 민원이 매우 많아 일선 경찰공무원 등이 많은 애로를 느끼고 있으며 급기야는 본고에서 검토할 사례의 경우와 같이 행정소송을 통해 뜻을 관철하고자 하는 경우까지 생겼다. 횡단보도의 설치와 관련한 대법원 판결(대법원 2000.10.27.선고, 98두8964판결)이 이제 처음 나왔지만 시민의 권리의식의 향상에 따른 소송의 증가경향으로 미루어 앞으로 이와 유사한 문제제기는 더욱 늘어날 것으로 전망된다. 이에 본고에서는 횡단보도의 설치와 관련한 행정소송에 대한 최근 대법원판결에 대한 심층분석을 통하여 그 의미와 문제점을 지적함으로써 앞으로 이와 유사한 사례에 대한 판단에 있어 방향성을 제시하였다. 즉 횡단보도 설치행위의 적법성과 관련한 소송에서 가능한 본안심리를 통해 국민의 권익구제의 기회 내지 가능성을 열어주는 것이 바람직하다는 점과 현재 원고적격의 범위가 확대되어 가고 있는 추세에 비추어 앞으로 횡단보도의 설치와 관련한 원고적격의 범위 역시 확대되는 것이 바람직하다는 방향에서 법규정에 대한 새로운 해석을 시도하였고 이를 통해 횡단보도의 설치 및 폐지에 따른 경찰 등 관계 행정청의 관심과 신중을 촉구하였다. 또한 횡단보도 설치행위의 처분성과 관련하여 횡단보도의 설치행위와 같은 일반적인 명령을 항고소송의 대상으로 할 필요성이 존재한다면 이른바 독일에서의 일반처분이라는 개념을 무리하게 받아들여 이를 행정행위의 한 유형으로 한다거나 우리 판례와 같이 "직접적이고 구체적인 법적 효과"를 미치는 명령이라는 명확치 않은 기준에 의하여 처분성을 인정하기보다는 일반적인 명령과 개별적인 행정행위를 구분하고 명령에 대하여도 취소소송의 대상으로 삼도록 하는 보다 명확하고 일관성 있는 논의전개를 제안하였다.

• Radiation Oncology Journal
• /
• v.8 no.2
• /
• pp.151-154
• /
• 1990

The acute effects of variable dos rates to total body irradiation (TBI) were investigaed with 600 cGy of single exposure in the mice as a preclinical model. Total 80 mice (ICR) were used. Twenty of which sewed as controls, receiving no irradiation. All irradiated mice showed a universal decline in their weight and white blood cell count. The degree of weight loss and leukopenia were similar at 3 different dos rate but slightly prominent with 15 cGy/minute group. The degree of recovery among the groups showed no dose rate dependence. Our results suggest that TBI with 15 cGy/mimute may be applicable for clinical therapy with careful evaluation of patient's condition.

• Journal of the Korean Society for information Management
• /
• v.17 no.1
• /
• pp.103-127
• /
• 2000

This study compared finding economic and energy information on the WWW to finding the same information on DIALOG, a traditional search service. Professional searchers answered 20 questions for end users using either of DIALOG and one Internet database (general search engine or Web database). The relevance of the results in both sets of answers was ranked by searchers and end-users, respectively. The study found that searching for information on the Web took at least twice as long as it did when using DIALOG. Relevance rating was a little higher for materials found on DIALOG. However, the relevance rating difference between two systems was not so higher than we expected. From the research results, we conclude that Internet database including Web database and general search engines is providing valuable information of economic and energy subject areas.