• Title/Summary/Keyword: long-run

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The furulamelllal study in order to obtain the hydrological design basis for hydrological structures in Korea (Run ofl estimate and Flood part) (한국에 있어서 제수문구조물의 설계의 기준을 주기 위한 수문학적 연구(류거, 홍수 편))

  • 박성우
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.8 no.1
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    • pp.1011-1034
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    • 1966
  • This thesis is the final report which has long been studied by the author to obtain the design basis for various hydrological constructions with the specific system suitable to the natural environmental conditions in Korea. This report is divided into two parts: one is to estimate runoff volume from watersheds and the other to estimate the peak discharge for a single storm. According to the result of observed runoff record from watersheds, it is known that Kajiyama formula is useful instrument in estimating runoff volume from watersheds in this country. But it has been found that this formula shows us 20-30% less than the actual flow. Therefore, when wihed to bring a better result, the watershed characteristics coefficient in this formula, that is, f-value, should be corrected to 0.5-0.8. As for the method to estimate peak discharge from drainage basin, the author proposes to classify it in two ways; one is small size watershed and the other large size watershed. The maximum -flood discharge rate $Q_p$ and time to peak Pt obtained from the observed record on the small size watershed are compared by various methods and formulas which are based upon the modern hydrological knowledge. But it was fou.d that it. was not a satisfied result. Therefore, the author proposes. tocomputate $Q_p$, to present 4.0-5.0% for the total runoff volume ${\Sigma}Q$.${\Sigma}Q$ is computed under the assumption of 30mm 103s in watershed per day and to change the theoritical total flow volume to one hour dura tion total flow rate when design daily storm is given. Time to peak Pt is derived from three parameters which are u,w,k. These are computed by relationship between total runoff volume (ha-m unit)and $Q_p$. (C.M.S. unit). Finally, the author checked out these results obtained from 51 hydrographs and got a satisfied result. Therefore the author suggested the model of design dimensionless unit-hydrograph. And the author believes that this model will be much available at none runoff record river site. In the large size watersheds in Korea when the maximum discharge occurs, the effective rainfall is two consequtive stormy days. So the loss in watershed was assutned as 6Omm/2days,and the author proposed 3-hour-daration hydrograph flow distribution percentage. This distribution percentage will be sure to form the hydrograph coordinate.

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A Prospect on the Changes in Short-term Cold Hardiness in "Campbell Early" Grapevine under the Future Warmer Winter in South Korea (남한의 겨울기온 상승 예측에 따른 포도 "캠벨얼리" 품종의 단기 내동성 변화 전망)

  • Chung, U-Ran;Yun, Jin-I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.10 no.3
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    • pp.94-101
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    • 2008
  • Warming trends during winter seasons in East Asian regions are expected to accelerate in the future according to the climate projection by the Inter-governmental Panel on Climate Change (IPCC). Warmer winters may affect short-term cold hardiness of deciduous fruit trees, and yet phenological observations are scant compared to long-term climate records in the regions. Dormancy depth, which can be estimated by daily temperature, is expected to serve as a reasonable proxy for physiological tolerance of flowering buds to low temperature in winter. In order to delineate the geographical pattern of short-term cold hardiness in grapevines, a selected dormancy depth model was parameterized for "Campbell Early", the major cultivar in South Korea. Gridded data sets of daily maximum and minimum temperature with a 270m cell spacing ("High Definition Digital Temperature Map", HDDTM) were prepared for the current climatological normal year (1971-2000) based on observations at the 56 Korea Meteorological Administration (KMA) stations and a geospatial interpolation scheme for correcting land surface effects (e.g., land use, topography, and site elevation). To generate relevant datasets for climatological normal years in the future, we combined a 25km-resolution, 2011-2100 temperature projection dataset covering South Korea (under the auspices of the IPCC-SRES A2 scenario) with the 1971-2000 HD-DTM. The dormancy depth model was run with the gridded datasets to estimate geographical pattern of change in the cold-hardiness period (the number of days between endo- and forced dormancy release) across South Korea for the normal years (1971-2000, 2011-2040, 2041-2070, and 2071-2100). Results showed that the cold-hardiness zone with 60 days or longer cold-tolerant period would diminish from 58% of the total land area of South Korea in 1971-2000 to 40% in 2011-2040, 14% in 2041-2070, and less than 3% in 2071-2100. This method can be applied to other deciduous fruit trees for delineating geographical shift of cold-hardiness zone under the projected climate change in the future, thereby providing valuable information for adaptation strategy in fruit industry.

A Development of concrete Pavement Material with Low Shrinkage and Reflection, High Strength and Performance (저수축 저반사 고강도 고내구성 콘크리트 포장재료 개발)

  • Kim, Hyo-Sung;Nam, Jeong-Hee;Eum, Ju-Yong;Cho, Yoon-Ho
    • International Journal of Highway Engineering
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    • v.11 no.1
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    • pp.13-24
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    • 2009
  • This study developed a high strength and performance concrete pavement material with low shrinkage and reflection of sunlight. Based on the literature review, a new mix-design of applying flash ash to improve the strength and performance of the concrete as well as to reduce the dry shrinkage is suggested. In addition, adding black pigment to reduce the reflection and technique of applying OAG (Optimized Aggregate Gradation) is also included. The result of the laboratory experiment indicates that the brightness and the reflection, which depends on the ratio of black pigment addition, did not deviate from the normal range. When OAG is considered for the mix-design, the strength and performance of the concrete improved greatly. In addition, the mix-design using fly ash reduced the dry shrinkage of concrete and improved the resistance to the permeation of chloride ion. Furthermore, the mix-design, which uses fly ash (25% replacement) and black pigment (3% addition) with the application of OAG, is found to be the most effective mix to reduce the shrinkage and reflection as well as improving the strength and performance of the concrete. The result of an economic analysis indicates that the initial construction cost of this proposed mix is more expensive than that of normal concrete pavement material. However, it can be more economic in the long run because the normal concrete pavement material is likely to cost more due to higher probability of maintenance and repair and higher social cost due to traffic accident, etc.

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Case Study on the Application of Chain Saw Machine for the Underground Marble Quarrying (갱내 대리석 채석을 위한 체인쏘머신 적용 사례연구)

  • Ju, Jaeyeol;Lee, Kwangpyo;Kim, Jaedong
    • Tunnel and Underground Space
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    • v.23 no.3
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    • pp.180-191
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    • 2013
  • The purpose of this research was to find an optimal quarrying for marble by analyzing the applicability and the work efficiency of a chain saw machine newly introduced in the underground Baekwoon mine. From the test results of the physical properties of Baekwoon marble, which affects the efficiency of rock cutting, it was found to have similar physical characteristics as the ones which are now being produced in the other areas in Korea. And especially it shows isotropic property, which can be thought to be advantageous as a dimensional stone. To check the long-term quality of the marble as a stone material, several tests such as corrosion resistance test and abrasion test were carried out. It was found to be vulnerable to acid rain with decrease of weight and seismic wave velocity after applying artificial rain at pH 5.6 for 50 times. The percentage of wear from abrasion test was 22.67%. The working time and cutting speed of the chain saw machine were recorded and analyzed during the test-run at the quarry. The overall work cycle was assorted into 9 unit operations and the operating time per each unit was drawn. The operating times for the two cutting patterns, which could be possibly applicable to the work site, were compared. The results indicated that the pattern B, that the cutting sequence was set to minimize the movement of the machine, showed 6% less working hours than the pattern A, which first cuts the outer boundary. With cutting pattern analysis, the ore body in the Baekwoon mine was 3 dimensionally modeled and a quarrying plan considering the existing conditions of the marble was suggested.

New Paradigm in exhibition organization at the National Museum of Contemporary Art ('연구 업무 전담제'를 통해 살펴보는 국립현대미술관 전시 기획의 새로운 패러다임)

  • Choi, Eun-Ju
    • The Journal of Art Theory & Practice
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    • no.3
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    • pp.67-84
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    • 2005
  • Since the evaluation of its intellectual activities and abilities is done by curator's capabilities, planning exhibition is very important as the final result achieved by their own knowledge, information, and research. ARPA(Advanced Research Project on Arts) is suggested as the system which enables curators responding simultaneously to the society in the times, based on its special characteristics. If this system settles well, which means that the curators at NMCA(National Museum of Contemporary Art, Korea) play their roles as the professionals in each of their fields, the goal of consolidating the status of museum as the representative national museum, and building up competent department of curators, will be achieved at the same time. To clarify above, the curators set up the various assignments of research about the types of arts such as painting, Korean painting, sculpture, installation, new-media, design, craft, photogarphy, architecture, etc. And they establish the art objects classified by the regions, such as the Northern American, Southern American, European, Asian, and other Third World countries. They elaborate art objects more on the history, the work, the artist, and the issue of contemporary art. Furthermore, when the curators devote deeper study to those research subjects, they can have the opportunities to design an exhibition upon the research. Today, the museum of art is 'The Place for Communication and Encounter', it is regarded important to share the aesthetical, creative values with current artists, and to understand mutually with the spectators. It is needed to improve the curator's work, in order to meet the demands of the times and even to advance. Because the form of 'exhibition' is the tool that reveals the identity NMCA aiming at, the motivation, the development, and the realization should be leaded by the curators, who are the mainstream of the museum. ARPA is a system for identifying the exhibition like mentioned above. The main purpose of this system is to produce synergy effect, having the researching, collecting work in liaison with planning exhibition. ARPA will be able to improve the quality of exhibition through the way of developing the exhibition, passing through the stable process in the long run. So far, I have referred to a new paradigm of the exhibition design at NMCA via ARPA. Yet, there still remain missions in reality, such as analyzing the previous exhibition and reshuffling personnel and system, which should be done. When these matters settled, these plans would be suggested practically. At this point, it is the most significant that NMCA is attempting to let others aware of the importance of exhibition planning based on research. when the ARPA and exhibition planning is conjoined together successfully, the competent exhibition will be achieved, which can offer a meaningful exhibition to the art world, strengthen infra structure thru exchanging with public museum in the region, and eventually, establish a network with museum in foreign countries.

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A Markov Chain Model for Population Distribution Prediction Considering Spatio-Temporal Characteristics by Migration Factors (이동요인별 시·공간적 인구이동 특성을 고려한 인구분포 예측: 마르코프 연쇄 모형을 활용하여)

  • Park, So Hyun;Lee, Keumsook
    • Journal of the Economic Geographical Society of Korea
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    • v.22 no.3
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    • pp.351-365
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    • 2019
  • This study aims to predict the changes in population distribution in Korea by considering spatio-temporal characteristics of major migration reasons. For the purpose, we analyze the spatio-temporal characteristics of each major migration reason(such as job, family, housing, and education) and estimate the transition probability, respectively. By appling Markov chain model processes with the ChapmanKolmogorov equation based on the transition probability, we predict the changes in the population distribution for the next six years. As the results, we found that there were differences of population changes by regions, while there were geographic movements into metropolitan areas and cities in general. The methodologies and the results presented in this study can be utilized for the provision of customized planning policies. In the long run, it can be used as a basis for planning and enforcing regionally tailored policies that strengthen inflow factors and improve outflow factors based on the trends of population inflow and outflow by region by movement factors as well as identify the patterns of population inflow and outflow in each region and predict future population volatility.

A Study for Fire Examples Involved in Engine Coolant leakage, Brake and Exhaust System Over-Heating of Heavy-Duty Truck Vehicle (대형 트럭 자동차의 엔진냉각수 누출, 제동 및 배기시스템 과열에 관련된 화재사례 고찰)

  • Lee, IL Kwon;Kook, Chang Ho;Ham, Sung Hoon;Lee, Young Suk;Hwang, Han Sub;You, Chang Bae;Moon, Hak Hoon;Jung, Dong Hwa;Ahn, Ho Cheol;Lee, Jeong Ho
    • Journal of the Korean Institute of Gas
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    • v.23 no.4
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    • pp.40-45
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    • 2019
  • This paper is a purpose to study the failure example for heavy-duty vehicle fire. The first example, the researcher found the engine over-heating phenomenon causing a coolant leakage by the sealing poor of head-gasket because of D-ring part deformation contacting with cylinder liner top-part and cylinder head. He certified a fire breakout by short transferred to surrounding wiring of air-cleaner. The second example, a brake lining by return fault of break operating S cam causing with much wear of a rear 4 wheel brake lining repeatably was worn by friction. In the long run, it became the cause of fire. The third example, the researcher knew the fire cause was came about the short of wire by overload of tilting motor when the driver tilted up the cap to inspect a engine. Therefore, a heavy-duty fire must minimize the fire occurrence by thorough controlling.

A Study on Improving Architect Property Insurance for Safety Accidents of Building (건축물 안전사고에 대비한 건축사 손해보험 개선 연구)

  • Kim, Myeongsoo
    • Korean Journal of Construction Engineering and Management
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    • v.20 no.1
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    • pp.32-40
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    • 2019
  • This study analyzed operating condition and the problems of damage compensation insunace (property insurance) for qualified architect and derived some suggsetions for improvement. The Certified Architects Act requires all building design and construction supervision to buy property insurance. This study proposes following suggestions to solve problems of current architect property insurance. Firstly, we need to increase the insurance purchasing rate of damage compensation insurance for qualified architect. It is necessary to clearly specify the matters concerning the submission of insurance policies by the architects, which is currently carried out by the Minister's official letter, in the form of official announcement. Secondly, proper insured amount should be adjusted. In order to insured substantial compensation capacity, total amount of insurance should be enlarged. Thirdly, the insurance period should be extended to one year after completion of building to allow compensation for accidents due to design negligence. Generally, the design defect can mostly be identified within one year after completion. Fourthly, insurance coverage should be extended. In the long run, it is essential to enlarge the scope of the security not only to property damage but also to human losses. Finally, an accident record sharing system should be established among insurance companies, so that proper insurance premiums or discounts can be made based on the system.

A Case Study on Reading Promotion Projects Led by the Korean Education Office Focused on the Project of 'Ulsan Studnets' Reading Day~ (교육청 주도의 독서진흥사업에 대한 사례연구 - '울산학생 책읽는데이~' 사업을 중심으로 -)

  • Youn, You-Ra;Lee, Soon Young
    • Journal of Korean Library and Information Science Society
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    • v.50 no.1
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    • pp.225-250
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    • 2019
  • The study aims to explore 'reading promotion projects' led by the Korean Education Office and to ponder meaning of the projects, and then to propose the future directions for the projects. To achieve the purpose, the study selected to analyze a reading promotion project called as "Ulsan Students' Reading Day~" by Ulsan MetropolitanCity Office of Education as a case and sample for the study. The study was designed to use two research methods and phases to explore the project in detail: documentary research and survey method. First, the study collected and analyzed the literatures and contents related to the projects but focused on examining progresses of the project such as situations from the introduction stage to the settlement stage. Second, the study conducted survey to collect data from teachers and students who have experienced the project in elementary, middle and high schools. The detailed contents of questionnaires contain current states of the project in each school, assessment of the project, and requirements for the project. The study found that the project resulted in positive influence to students' reading skills and education. In spite of these positive results, it is necessary to develop altenatives to solve some limts in the current states of the project. Reading promotion projects, in long run, need to have profeissional staffs with responsbility for managing the projects, to improve environments for reading promotion, and to encourage students' voluntary participation to the projects.

Comparative Analysis between Super Loop and FreeRTOS Methods for Arduino Multitasking (아두이노 멀티 태스킹을 위한 수퍼루프 방식과 FreeRTOS 방식의 비교 분석)

  • Gong, Dong-Hwan;Shin, Seung-Jung
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.6
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    • pp.133-137
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    • 2018
  • Arduino is a small microcomputer that is used in a variety of industry fields and especially is widely used as an open source hardware IoT device. The multi-tasking method of Arduino is divided into super loop timing and RTOS thread method. The super loop timing method is simple and easy to understand. However, when one task is long, it affects the execution of the next task. In addition, RTOS threading has the advantage of being able to run without being influenced by other work time. However, Arduino, a small microcomputer, has a disadvantage in that, when the number of threads increases, the context switching time of the thread causes additional time not included in the super loop timing method have. In this paper, we use Arduino Uno R3 and FreeRTOS to analyze these different features, and the task for the experiment is to send 8000 digital signals to the built-in LED port. If two tasks of the same size are executed, the super loop method executes 3 ms faster than FreeRTOS multitasking. If multiple tasks are executed simultaneously, superloop type task is sequential execution and difference in execution time between first task and last task is large. FreeRTOS method can be executed concurrently, but execution time delay of about 30 ms occurs in context switching time.