• CDE review
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• v.3 no.2
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• pp.34-40
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• 1997

• Korean Architects
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• s.474
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• pp.16-17
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• 2008

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2575-2582
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• 2013

In the delivery systems for public construction works, design-build methods such as turn-key and alternative have contributed to improving the quality of structures and developing the construction technology. However, it is pointed out that construction based on a design-build method is likely to waste a budget due to its higher contract price than construction based on a design-bid-build method. Other issues such as contract monopoly, bid rigging and deliberation irregularity in design-build. Since there are not much works have been accomplished to comparatively analyze the actual performance and effect based on delivery methods, discussing and judging the performance and effect of each deliver method with limited information could lead to an error. Thus, this study by extensively investigates the actual project cost data, ranging from contract price to the construction cost of the public construction works and comparatively analyzed the characteristics of each delivery method about cost structure and fluctuation trend. This work is expected to assist stake-holders in properly understanding delivery systems for public construction works and promoting their efficient management.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.141-151
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• 2020

Purpose: This study aimed to quantify the influence of tooth position within the field-of-view (FOV) on cone-beam computed tomography (CBCT) imaging artifacts' intensity when assessing teeth restored with various intracanal materials. Materials and Methods: Seventy single-rooted teeth were divided into 7 groups (10 teeth per group): NiCr post (NC), AgPd post (AP), metal core fiberglass post (MCFG), fiberglass post (FG), anatomical fiberglass post (AFG), fiberglass post cemented with core build-up cement (FGCo), and anatomical fiberglass post cemented with core build-up cement (AFGCo). All posts were cemented using a regular dual-curing resin cement (Allcem), except FGCo and AFGCo which were cemented with a core build-up dual-curing resin cement (AllcemCore). Each tooth was scanned on a CS9000 in 5 positions within the FOV: a central position, anterior horizontal peripheral, peripheral superior, peripheral inferior, and posterior horizontal peripheral position. Hyperdense, hypodense, remaining teeth areas and ROI areas were quantitatively analyzed using ImageJ software. Results: Posterior horizontal peripheral position increased the intensity of artifacts on FGCo and AFGCo post groups (P<0.05), and specifically the hypodense artifact intensity on FG and AFG post groups (P<0.05). NC and AP groups presented greater intensity of artifacts than any other post groups(P<0.05). Conclusion: Artifact intensity increases in the presence of high atomic number materials and when the object is not centered within the FOV. The impact of positioning within the FOV on artifact was greater for fiberglass posts cemented with core build-up dual-curing cement than for metal posts and fiberglass posts cemented with regular dual-curing cement.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.1
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• pp.1-10
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• 2000

The main purpose of this research is to show the consideration of the geographical effects related with its features and configuration on the height of the wall in Hwasong. The method of this research is based on old documentary records and actual measuring. The result of this research is to take advantage of nature geographical features and configuration. First the castle of wall construction is based on outside defensive protection, mainly it was made of stones or bricks. And took advantage of its natural environment. According to circumstance, there were two kinds of general method to build the wall., Second It was considered, They had so many difficulty to move stones to build wall, especially to rugged hilly steep mountain. Third There were three kinds of stones to build wall, Bottom stones were piled with Big stones, because of its stability. Third There were three kinds of stones to build wall, Bottom stones were piled with Big stones, because of its stability. On top of the wall was built with small stones it shows good harmony with small, middle, big size stones. It is considered not only stability but also beauty of appearance. Fourth Placing ChiSung was able to adjust height of wall low at the same time it was also taken advantage of a active defensive power. The suggestion of this research is to take advantage f nature geographical features and at the same time it was a perfect way to save the cost of construction. The further research of this should be continued to deepen because, it is the early stage, so it is maningful of eoffering a guidance for the furder research. in this research has a number of important question remain unsolved.

• Korean Journal of Construction Engineering and Management
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• v.7 no.6
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• pp.121-131
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• 2006

Since "Act on Private Participation in Infrastructure" were changed in January 2005, BTL(Build-Transfer-Lease) projects of Private Participation In Infrastructure was introduced in the domestic construction market for the purpose of providing public facilities with the public. Selecting the most qualified Promoter should be considered discreetly in BTL projects because BTL projects is for projects with approximately thirty year project life cycle, plan, construction, operating, maintenance and obviously the success of the project totally depends on the capability and role of concessionaire. However, score for cost is likely to influence designating concessionaire to take the project. Accordingly, low bid contract with too much competition could decrease the quality of the construction plan and operating plan. Thus, this study did preliminary research and documents on problems of evaluation criteria for designating concessionaire in BTL projects, and proposed improvement program by doing questionnaire over specialists of each field.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.217-223
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• 2019

The application of 3D printing technology is expanding due to the production of the complex-shape parts and the one-step manufacturing process. Moreover, various technical solutions in 3D printing are emerging through continuous research and development. Representative technologies include SLS technology, in which a desired area is sintered and laminated by irradiating a powder-type material with a laser. In addition, high-performance engineering plastic parts are being manufactured in increasing numbers. In this study, tensile specimens were fabricated from polyamide 12, a widely available polymer, and the glass bead-reinforced polyamide 12. The specimen-build orientation was divided into 0°, 45°, and 90° on the fabrication platform, and the tensile test temperature was -25℃, 25℃, and 60℃. The test results showed that the tensile modulus of both materials decreases as the build orientation becomes closer to 90°. In addition, the tensile strength of glass bead-reinforced PA12 showed more dependence on the build orientation than PA12. In addition, the tensile modulus and tensile strength decreased with increasing test temperature.

• Ocean and Polar Research
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• v.25 no.1
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• pp.63-74
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• 2003

The build-up of the heat field in shallow coastal water due to a point source has been investigated using an analytical solution of a time-integral form derived by extending the solutions by Holley(1969) and also presented in Harleman (1971). The uniform water depth is assumed with non-isotropic turbulent dispersion. The alongshore-flow is assumed to be uni-directional, spatially uniform and oscillatory. Due to the presence of the oscillatory alongshore-flow, the heat build-up occurs in an oscillatory manner, and the excess temperature thereby fluctuates in that course and even in the quasi-steady state. A series of calculations reveal that proper choices of the decay coefficient as well as dispersion coefficients are critical to the reliable prediction of the excess temperature field. The dispersion coefficients determine the absolute values of the excess temperature and characterize the shoreline profile, particularly within the tidal excursion distance, while the decay coefficient determines the absolute value of the excess temperature and the convergence rate to that of the quasi-steady state. Within the e-folding time scale $1/k_d$ (where $k_d$ is the heat decay coefficient), heat build-up occurs more than 90% of the quasi-steady state values in a region within a tidal excursion distance (L), while occurs increasingly less the farther we go to the downstream direction (about 80% at 1.25L, and 70% at 1.5L). Calculations with onshore and offshore discharges indicate that thermal spreading in the direction of the shoreline is reduced as the shoreline constraint which controls the lateral mixing is reduced. The importance of collecting long-term records of in situ meteorological conditions and clarifying the definition of the heat loss coefficient is addressed. Interactive use of analytical and numerical modeling is recommended as a desirable way to obtain a reliable estimate of the far-field excess temperature along with extensive field measurements.

• Korean Journal of Optics and Photonics
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• v.21 no.1
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• pp.16-20
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• 2010

In this study, we have fabricated a fiber-optic dosimeter using an organic scintillator and a plastic optical fiber. The dosimeter measure skin dose and percentage depth dose in a build-up region for an incident high energy photon beam. The scintillating light generated in the organic sensor probe embedded in a solid water phantom is guided by 30 m plastic optical fiber to a light-measuring device such as a PMT or an electrometer. In addition, using a fiber-optic dosimeter or a GAFCHROMIC EBT film, skin dose and percentage depth dose in the build-up region are measured and compared.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.278-283
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• 2006

Koran Government introduced BTL(Build-Transfer-Lease) to provide convenience through early supplying infrastructure and plans to invest 8,315million dollar to 84 projects of 15 BTL type involving official residence and railroad. But some of construction company hates to invest BTL projects because of its low earning rate. In addition if we correctively apply project which partly has profitability to BTL, the earnning rate declines more seriously. So this paper presents BTL+BTO model which operates BTL in the non-profitable parts to improve convenience of users and BTO in the profitable parts to improve earning rate. BTL+BTO model based on operate period was presented and its suitability was confirmed by applting 00 region official residence project.