• Journal of Korean Institute of Industrial Engineers
• /
• v.26 no.4
• /
• pp.384-391
• /
• 2000

Most of the previous works on classical location models are based on the assumption that the value(or utilities) of inventory remains constants over time. In this study a special case of location problem is studied for both ameliorating and deteriorating items in two-echelon supply-chain management such as agricultural and fishery products. The objective of this study is to determine the minimum number of storage facilities among a discrete set of location sites so that the probability for each customer to be covered is not less than a critical value. We have formulated this problem using stochastic set-covering problem which can be solved by 0-1 programming method. Also we developed a computer program and applied to a set of problems for fish culture storage and distribution centers and the sample results well show the impact of ameliorating and deteriorating rate on the location problem. For the further study, a graphical user-interface with visualization for input and output is needed to be developed.

• Computers and Concrete
• /
• v.26 no.6
• /
• pp.577-585
• /
• 2020

By the increasing amount of waste materials, it eventually dumped into the environment and covering a larger area of the landfill which cause several environmental pollution problems. The utilization of Palm Kernal Shell Ash (PKSA) in concrete might bring a great benefit in addressing both environmental and economic issues. This article investigates the effect of PKSA as a partial cement replacement of High Strength Concrete (HSC). Several concrete mixtures were prepared with different PKSA of 0%, 10%, 20%, and 30% replaced by the cement mass. This procedure was replicated twice for the two different target mean strengths of 40 MPa and 50 MPa. The mixtures were prepared to test different fresh and hardened properties of HSC including slump test, the compressive strength of 3, 7, 14, 28, and 90 days, flexural strength of 28-days, drying shrinkage, density measurement, and sorptivity. It was observed 10% PKSA replacement as optimum percentage which reduced the drying shrinkage, sorptivity, and density and improved the late-age compressive strength of concrete.

• Educational Technology International
• /
• v.8 no.2
• /
• pp.73-91
• /
• 2007

The purpose of this study is to explore tools for systemic and integrated teaching analysis in recognition of problems derived from the existing teaching analysis which have been held fragmentarily and temporarily. In order to do so, a teaching analysis tools is identified by examining the current services of video-taping and analysis, which are the most representative teaching analysis methods among the Centers for Teaching and Learning (CTLs) in Korea, and by redefining teaching analysis through literature review. A teaching analysis is to be done to challenge teachers to change and grow by providing a motive to reflect on the act of teaching and carry out improvements, and it has to be held covering the general act of teaching and examined through diverse methods in systemic and multidimensional perspectives over a full period of teaching. In this study, an act of teaching is examined in four areas: planning, teaching skill, evaluation and reflection, and teaching analysis frameworks according to an act of teaching are suggested by periods of before, during, and after a term. Teaching analysis methods are also suggested by the frameworks.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.5
• /
• pp.577-586
• /
• 1999

Two problems with jet injection through the cylindrical film cooling hole are 1) penetration of jet into mainstream rather than covering the surface at high blowing rates and 2) nonuniformity of the film cooling effectiveness in the lateral direction. Compound angle injection is employed to reduce those two problems. Compound angle injection increases the film cooling effectiveness and spreads more widely. However, there is still lift off at high blowing rates. Shaped film cooling hole is a possible means to reduce those two problems. Film cooling with the shaped hole is investigated in this study experimentally. Film cooling hole used in present study is a shaped hole with conically enlarged exit and Inlet-to-exit area ratio is 2.55. Naphthalene sublimation method has been employed to study the local heat/mass transfer coefficient and film cooling effectiveness for compound injection angles and various blowing rates around the shaped film cooling hole. Enlarged hole exit area reduces the momentum of the jet at the hole exit and prevents the penetration of injected jet into the mainstream effectively. Hence, higher and more uniform film cooling effectiveness values are obtained even at relatively high blowing rates and the film cooling jet spreads more widely with the shaped film cooling hole. And the injected jet protects the surface effectively at low blowing rates and spreads more widely with the compound angle injections than the axial injection.

• Journal of Digital Convergence
• /
• v.14 no.3
• /
• pp.35-43
• /
• 2016

Internal and external environment changes surrounding our society are pressing our government to solve a lot of difficult problems. These problems are more likely to be solved by a number of ministries and agencies, rather than a single ministry or agency. Thus collaboration is a necessary strategy to increase government's problem-solving skills. This study examines determinants of successful collaboration by analysing cases of local governments that solved uneasy problems covering many ministries after persistent efforts which have been controversial issues in our society. First, theoretical approach for collaboration and its matrix is examined. Second, interviews of government officers are analyzed to study collaboration cases. Finally, Strategic points of view are discussed to promote collaboration within government sectors. The results show that common goal sharing, incentives and supporting systems play important roles in inducing collaboration.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.10 no.2
• /
• pp.1-15
• /
• 2007

A variety of revegetation methods are being utilized and developed. However, most of revegetation methods used on highway slopes in Korea are based on foreign-introduced plant varieties to stabilize road surfaces and to administer afforestation for surface covering at an earlier phase. Therefore. it results in various problems. such as failure to achieve harmony with the surrounding vegetation and 10 cause re-denudation of slopes as the foreign-in introduced plant varieties wane out from 2~3 years after hydro-seeding, etc. In addition, some of the revegetation plants seeded in the earlier phase grow excessively high, thus causes successional problems, such as to inhibit the invasion of the secondary vegetation from the surrounding areas, etc. Therefore, in this study, 160 slopes located in the nationwide express highways have been investigated and analyzed in order to produce basic data for restoration of ecological environment in slopes created on a long-term basis by investigating and analyzing locational characteristics of cut and filled slopes in express highways, status of revegetation methods, characteristics of soil and plant-ecological environment. 1. Investigation on cut and embanked slopes in express highways was carried out in the total of 160 locations, which include 108 cut slopes and 52 embanked slopes. As a whole, the most frequently used revegetation method was seed spray, which was found to be used in the total of 55 target slops investigated. 2. Planting method of Wistaria floribunda applied to some of the blasted rock zones was found to cause damages as Wistaria floribunda trailed up the surrounding vegetation and the secondary invaded trees. In order to prevent this, this method must be used only in the lowest parts of large-sized slopes. Also, it will be required to administer continuous management and maintenance in the areas already planted with this plants. 3. The areas of blasted rock and ripping rock slopes were applied with coir net (net + seeding) method. However, many of these areas failed in achieving ground covering. Most areas where revegetation was in progress, they were covered with Eragrostis curvula(Weeping lovegrass) only. In areas with soil, such as decomposition of granite, where afforestation is difficult. In this slopes, soil base must be improved by hrdroseeding with thin-layer vegetation base application methods in order to achieve success in afforestation with native plants. 4. Woody species, rather than herb species, are more helpful in stabilization of slope surfaces. Therefore, it is important to be able to grow and protect woody species on highway slopes. Growth of woody vegetation is most largely influenced by soil depth. Thus, when hydro-seeding woody plants, it is recommended to apply at the upper layer of the slopes, which is capable to sufficiently provide the fundamentals required in plant growth.

• Radiation Oncology Journal
• /
• v.1 no.1
• /
• pp.25-28
• /
• 1983

Anterior and posterior parallel opposed field technique covering entire neck is desirable for elimination of junctional problems in treating upper neck with bilateral parallel opposed fields and lower neck with anterior one field. For good dose distribution in neck, dose in build-up region should be high for anterior field and should be low for posterior field. And so, with 10 MV X-ray, lead absorber was used for anterior field only. The adequate thickness of lead absorber, absorber-skin separation, width of central cord block for posterior field and anterior & posterior field weight were studied using film dosimery. The results are as follows. 1. As the thickness of the lead absorber increased the dose in build-up region increased. 2. As the absorber-skin separation decreased the dose in build-up region increased. 3. The adequate thickness of lead absorber was around 5.6mm. 4. The adequate absorber-skin separation was around 5cm. 5. The adequate posterior cord block width was 3cm. 6. 4:1 weighting for anterior and posterior field was adequate. And so with this technique, adequate dose distribution could be made as well as elimination junction problems.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.2
• /
• pp.239-246
• /
• 2020

In this paper, an automatic dewatering system for drying water from umbrellas is proposed. In the past, there were problems that users had to put on plastic for removing the water from umbrella by covering it with a plastic or using a water dryer that removes water by manually touching the umbrella to the water surface. But this method was hard to expect. To solve these problems, an air compressor was used to develop a system to remove water from the umbrella by detecting the weight of the umbrella with pressure sensor when the user puts the umbrella into the dewatering machine and driving the motor. It is expected that this invention will have economic and environmental effects by eliminating the use of waste vinyl.

• Korean Journal of Construction Engineering and Management
• /
• v.12 no.3
• /
• pp.53-61
• /
• 2011

After several collapse accidents of large structures in the early 1990s in Korea, the government enacted a law that architectural, engineering and construction firms are obliged to have insurance for projects over a certain size. Particularly, with regard to insurance in design and construction supervision works (i.e. engineering insurance), although several operation-based problems were pointed out from practitioners, still little research has been done on analyzing current regnlartory and operational state and suggesting policy alternatives. Hence, this study applies Delphi technique to solicit current operational problems and propose a series of improvements on engineering insurance based on interview surveys targeting major market participants: municipalities, engineering firms, and insurance companies. Key findings culminate in adopting guarantee limits based on credit evaluation, abrogating joint surety, covering a loss of life, increasing insurance entrance fee, extending time covered, and etc. Reaching a consensus on the proposed alternatives between the market participants will form the foundation for sound developments of construction design and engineering industry.

• Journal of Korean Society for Geospatial Information Science
• /
• v.4 no.2 s.8
• /
• pp.63-77
• /
• 1996

This study suggests that experts' group decision support system (Experts'GDSS) should be helpful to solve specific planning/design problems. Dealing with AHP (Analytic Hierarchical Process), as a group decision model, maximal covering model, as a facility allocation model, and GIS (Geographic Information System; ARC/INFO in this study), as a spatial representation model, this study seeks to examine the implication of GDSS (Group Decision Support System) in the housing facility allocation. The results of this study clearly demonstrated that experts' GDSS acted its positive role, systematically providing the relative weights among the planning variables and objectives. Among different expert groups (e.g., planners, scholars, and public administrators), this study showed that there were certain differences in their decision structures, which generated different solutions in facility allocation. The further study, however, remains to investigate the more systematic implementation of GDSS in planning problems; for example, reducing the conflicts between different groups with different purposes.