• KDI Journal of Economic Policy
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• v.18 no.1
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• pp.217-270
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• 1996

실제(實際)GDP와 잠재(潛在)GDP의 차이로 정의되는 GDP갭의 변화는 경기변동(景氣變動)을 반영하는 동시에 실물경제의 흐름과 물가압력을 연계하는 거시경제변수라고 할 수 있다. 그러나 통상적인 의미의 GDP갭은 경기변동의 근원적(根源的) 요인(要因)(sources of business cycle) 에 대한 설명력이 결여되어 있음을 감안하여 본고(本稿)에서는 주로 경제의 총수요(總需要) 측면에 초점을 맞추어 GDP갭을 추정하였다. 추정된 GDP갭의 변화패턴이 경기변동의 정점(頂點)및 저점(底點)과 거의 일치(一致)하는 동시에 과거 경제운영 과정에서의 주요 정책변화(政策變化)와 일관성(一貫性)을 보이고 있어 현실경제에 대한 설명력이 높은 것으로 평가(評價)된다. 또한 추정된 GDP갭은 수요봉인(需要奉引)에 의한 물가상승(物價上昇)과 밀접하게 연계되어 있으며, 총통화(總通貨) 및 금리(金利)의 변화(變化)와도 높은 상관관계를 나타내고 있다. 경기변동(景氣變動)의 요인(要因)을 수요(需要)측면과 공급(供給)측면으로 구분하여 살펴본 결과 수요변화는 단기적인 성장효과에도 불구하고 장기적(長期的)으로는 물가(物價)에 보다 큰 영향을 미치고 있는 반면, 공급측면의 변화는 장단기(長短期) 모두에 있어서 성장(成長)과 물가(物價)에 지속적인 영향을 미치는 것으로 추정되었다. 또한 물가안정을 위한 총수요긴축(總需要緊縮)에 수반되는 단기적인 성장둔화(成長鈍化) 효과가 상대적으로 큰 것으로 나타나고 있으며, 우리 경제의 높은 해외의존도(海外依存度)로 인하여 해외(海外)로부터의 공급충격에 따른 실물부문(實物部門)의 경기변동이 적지 않았다는 결과가 도출되었다. 이러한 실증분석 결과의 시사점은 (1) 물가안정에 수반되는 경제적(經濟的) 비용(費用)이 크므로 처음부터 물가압력(物價壓力)이 확대되지 않도록 경제(經濟)를 안정적(安定的)으로 운영하는 것이 바람직하며, (2) 자본자유화(資本自由化) 등의 진전으로 실물부문뿐만 아니라 금융부문(金融部門)도 해외(海外)로부터의 공급충격에 직면하게 될 것으로 예상되므로 임금(賃金) 등의 요소비용(要素費用) 안정과 함께 구조조정(構造調整) 및 경쟁(競爭) 촉진(促進) 등을 통하여 경제의 체질(體質)을 개선(改善)하는 노력이 요구된다는 것으로 요약할 수 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.299-304
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• 2005

The design procedures of full-scale combustion chamber with chamber pressure of 53bara, mass flow rate of 90kg/s, combustion efficiency of $94\%$ and specific impulse at ground of 253sec were described. The details of combustion performance and geometrical parameters were also given. Full-scale combustion chamber consists of the combustor head with injector/baffle and the chamber/nozzle with regenerative cooling channels. The design results of combustion chamber with ablative materials, detachable injector head with SUS baffle or baffle injector and chamber body for ground hot firing tests were given in this paper.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.128-135
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• 2007

Combustion characteristics of full-scale gas generators were studied experimentally by changing the injector number installed at the injector head. Three full-scale gas generators were utilized; they have same total mass flow rate but mass flow rates per injector are different. Thirteen, nineteen and thirty seven injectors, which have internal-mixing and double-swirl characteristics, are distributed in injector heads, respectively. The results showed that pressure fluctuations in the gas generators with 13 and 19 injectors didn't occur around longitudinal resonant frequency, however longitudinal-mode pressure fluctuation appeared slightly in the gas generator with 37 injectors. As the number of injectors increased, deviations of temperature distribution in the combustion chamber decreased gradually, but the damage of injector LOx posts became a little severe.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.606-609
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• 2008

Traditionally, the feasibility of the private investment is determined by NPV(Net Presented Value) based on DCF(Discounted Cash Flow) and the volume of government's subsidiary without quantifying the effect of overturn share ratio and MRG(Minimum Revenue Guarantee), these variables which can seriously effect on the economic feasibility. One of the most important reasons why these variables are not underestimated is that the quantifying methods are insufficiently or so complicatedly studied to apply practically the real project. Therefore, this study suggests the modified binominal option model to estimate the overturn share ratio and MRG and estimates how much these variables impact the private investment. Also, these results are helpful to estimate how much the government's subsidiary can be reduced.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1741-1751
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• 2013

The main purpose of this study is to investigate the static behavior of a prestressed concrete (PSC) girder using pre-tension method. A 30m long full-scale pretension PSC girder is fabricated by the portable fabrication system and tested. All results have been compared to those obtained from F.E.A results. Deflections at the middle of girders have been measured for evaluation. Also, strains of concrete at the middle of span have been measured. From the results of experimental, the load when initial crack was developed was obtained to be 1.75 time the unfactered design load in the full-scale girder specimen. Also, the data of specimen are satisfied the desgin requirements of ductility on the Korea Bridge Design Specification(2010). In service state, the vertical deflection at center of test specimen when a initial crack was developed is satisfied the vertical deflection requirement under live load of the Korea Bridge Design Specification(2010). To verify the experimental results, we numerical analyze the test and confirmed that the data were similar with results from the test above. The pretension girder fabricated in site were found to have enough strength for safety under and after construction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.171-176
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• 2016

This paper proposes road safety facilities applying Hot-dip zinc-aluminum-magnesium alloy-coated steel sheets and coils to reduce the loss of function caused by the corrosion of steel in the service state. Vehicle crash simulations and full-scale crash tests were carried out to provide reliable information on evaluating the crash performance with the products of road safety facilities built with hot-dip zinc-aluminum-magnesium alloy-coated steel. From the results of the simulations and full-scale crash tests, the impact behaviors evaluated by the three-dimensional crash simulations considering the strain-rate dependency in a constitutive model were similar to those obtained from the full-scale crash test results. The full-scale crash test results met the crashworthiness evaluation criteria; hence, the proposed bridge barrier in this paper is ready for field applications.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.163-168
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• 2006

The combustion performance tests of a 30 tonf-class full-scale combustion chamber performed with kerosene as a coolant were described. The combustion chamber has chamber pressure of 53bara and propellant flow mass rate of 90kg/s. Since it was first firing test for 30tonf-class combustion chamber using kerosene cooling, kerosene coolant mass flow rate of 32kg/s which correspond to 120% of design mass flow rate were performed. Then, the firing test with kerosene mass flow rate of 25kg/s were successfully performed. The test results are described and the results showed that the kerosene cooling performance of this combustion chamber is sufficient and the firing test with regenerative cooling is feasible.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.309-315
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• 2006

Effects of injector or design on combustion characteristics of full-scale gas generators were studied. Three full-scale gas generators, which have same total mass flow rate but mass flow rate per injector is different depending on their designs, were manufactured. Thirteen, nineteen and thirty seven injectors, which have internal-mixing and double-swirl characteristics, are distributed in injector heads, respectively. The results showed that special pressure fluctuations in the gas generators with 13 and 19 injectors didn't appear around longitudinal resonant frequency, but small longitudinal-mode instability appeared in the gas generator with 37 injectors. As the number of injectors installed in injector heads increased, temperature distribution in combustion chambers showed small deviations, but the damage of LOx posts increased.

• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.177-185
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• 1996

Four types of experiments were performed to check the similitude of member behavior between prototype and 1 /10 scale models : (1) Test of slender columns with P-$\Delta$ effect, (2) Test of short columns with and without confinement steel, (3) Test of simple beams without stirrups, and (4) 'T-beam test. Based on the results of experiments, the conclusions were made as follows : (1) The P-$\Delta$ effect of slender columns can be almost exactly represented by 1/10 scale model. (2) The effect of confinement on short columns by the hoop steel can be also roughly simulated by 1/10 scale model. (3) The failure modes of simple beams without stirrups are brittle shear failures in prototype whereas those of 1/10 scale models are the ductile yielding of tension steel followed by large diagonal tension cracking and compressive concrete failure. (4) The behaviors of prototype and 1/10 scale model in T-beams appear very similar.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.805-816
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• 2010

For earthquake simulation test it is essential to make sure the similitude in behaviors between the full scale prototype and the reduced scale model. This paper presents the test results obtained through the cyclic lateral-force test, on two-story RC wall subassemblages. A lower 2-story portion of the prototype structure was selected as subassemblages. The global behavior such as the strength and ductility, and the local behavior such as flexural, shear and uplift deformation were measured. The test results of the 3 : 5 scale specimens representing the prototype were compared with those of 1 : 7 scale models. Two types of subassemblages were used: One with lintel beams and one without lintel beams. The comparison shows that 1 : 7 scale model simulated in general successfully the global and local behaviors of the prototype.