• Journal of the Korean housing association
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• v.23 no.2
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• pp.89-98
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• 2012

As the construction of multi-family housings, especially apartments, has been increased since 1970s, the multi-family housing becomes one of the main housing types in Korea. With the increase of multi-family housings, managing them becomes an important issue. Since 2010, the government has made a lowest price award system by a competitive bid compulsory to promote the development of housing management systems. Although competitive bids were implemented, the maintenance company was finally selected by the price without any other consideration. Consequently, the quality of management service was not enhanced. The purpose of this study is to suggest the improvement scheme of multi-family housing management system. In this study, the bidding data of "K-apt", the bidding method and the successful tendered price are analyzed. The results of analyzing bidding materials, the proportion of applying a lowest price system was 67.7%. Also many diverse ways to select the best management company were used, but most of these ways were violate the law and guidelines of Ministry of Land, Transport and Maritime Affairs. It meant that the lowest price award system was not implemented by strict standards and didn't correspond with the needs of residents of apartment. This condition made the housing maintenance quality low and deteriorated the management industry development. To enhance this condition, a new standard to select the management company, which are included contents of quality of managing quality, management expenses and companies' soundness, is necessary.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2011.04a
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• pp.296-300
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• 2011

It's well known that housing is one of the largest holdings in household wealth and at the same time the majority of households highly concentrate on it for their wealth accumulation. Coupled with a low interest rate and increasing housing price, the rationale is conspicuous and the propensity to debt-financed consumption becomes strengthened. This research was to examine the risk of home financing. In doing so, the study utilized several secondary data to identify the characteristics of households who finance loans for home buying in three regions of the nation - so-called Bubble 7, Seoul Metropolitan Area, and others. Based on the 2009 KB survey, the major findings were as follows: the majority of the studied households in Seoul Metropolitan Area who owned a house lived in rental housing, housing accounted for 89% of the household wealth, and home loans taken on were a ballon payment amortized for a short-term period (5 years) with an adjustable interest rate. In addition, the payment method most of the households depend on is income. The financing mechanism fueled debt load of the households, and further they are financially very vulnerable to such factors as increase in interest rate, unemployment and market downturn. In the absence of understanding the financial system, the consumption behavior leads to house-poor, so that financial accountability and ethics are addressed while the intervention of the government in home financing system should be more cautious but stimulate financial soundness in household wealth accumulation.

• Journal of the Korean Society for Heat Treatment
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• v.33 no.3
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• pp.99-106
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• 2020

Selective laser melting (SLM) is an additive manufacturing process by melting metallic powders and stacking into layers, and can product complex shapes or near-net-shape (NNS) that are difficult to product by conventional processes. Also, SLM process is able to raise the efficiency of production by creating a streamlined manufacturing process. For manufacturing in SLM process using Ti-6Al-4V powder, analysis of microstructural evolution and evaluation of mechanical properties are essential because of rapid melting and solidification process of powders according to high laser power and rapid scan speed. In addition, it requires a post-processing because the soundness and mechanical properties are degraded by defects such as pore, un-melted powder, lack-of-fusion, etc. In this study, hot isostatic press (HIP) was conducted as a post-processing on SLM-printed Ti-6Al-4V alloy. Microstructure of post-processed Ti-6Al-4V alloy was compared to as-built Ti-6Al-4V, and the evolution of quasi-static (Vickers hardness, room temperature tensile characteristic) and dynamic (high-cycle fatigue characteristic) mechanical properties were analyzed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.10
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• pp.1877-1889
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• 1992

Upsetting is performed in open-die press forging to deform metal in all directions in order to enhance soundness of a product and reduce directionality of properties caused by casting. It is necessary to ensure sufficient forging ratio for subsequent cogging operations and consolidate the void along the centerline. To obtain these benefits, the upper die shape (dome and dished shape) is considered as an upsetting parameter. Thermo-viscoplastic finite element analysis has been carried out so as to understand the influence of upper die shape on the effective strain, hydrostatic stress and temperature in the upset-forged ingots without internal defects. The analysis is focused on the investigation into internal void closure in ingots with pipe holes and circular voids. The computational results have shown that the volume fraction of the void is independent of the circular void size and the closure of internal voids is much more influenced by the effective strain than the hydrostatic stress around the void. It is finally suggested that the height reduction must be over 35% for consolidation of internal voids.

• 한국도로학회:학술대회논문집
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• 2002.10a
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• pp.89-92
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• 2002

The objective of this research is to evaluate engineering properties of recycled aggregates, slag as coarse & fine aggregate and waste foundry sand(WFS) as fine aggregate, in hot mix asphalt(HMA). In this research, soundness, gradation and particle analysis, abrasion, specific gravity and absorption test were carried out. The optimum asphalt binder content(OAC) for various HMA combinations of recycled aggregate was determined by Marshall Mix Design. The ranges determined is between 7.2% and 7.5%. Indirect tensile test, resilient modulus test, creep test were carried out for characterization of rutting behavior of various combination of HMA. Judging from the limited tests, the HMA with recycled aggregates is not as good rutting resistance as the HMA with common aggregates. After finishing the Wheel tracking test, the application or feasibility for the use of recycled aggregate as asphalt paving material will be determined.

• Journal of Veterinary Clinics
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• v.28 no.4
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• pp.365-368
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• 2011

Next to performing an expert physical examination, a blood sample submitted for a complete blood count is the most basic tool available to owners or veterinary practitioners. Reference values of complete blood count were determined at 6 different ages in 114 Thoroughbred foals during the second month of life. Hematologic results were as follows: RBC 8.2-10.5 ($10^6/{\mu}l$), Hb 10.9-13.3 (g/dl), HCT 28.2-35.2 (%), MCV 30.7-35.8 (fL), MCH 11.9-13.5 (pg), MCHC 37.9-40.5 (g/dl), RDW 24.5-25.7 (%), PLT 146.3-256.4 ($10^3/{\mu}l$), MPV 6.7-8.3(fL), total WBC 8.1-12.5 ($10^3/{\mu}l$), basophils 0.0 ($10^3/{\mu}l$), eosinophils 0.0-0.3 ($10^3/{\mu}l$), neutrophils 2.4-8.6 ($10^3/{\mu}l$), lymphocytes 1.8-2.9 ($10^3/{\mu}l$) and monocytes 0.0-1.4 ($10^3/{\mu}l$). The results of this study serve as reference ranges for Thoroughbred neonatal foals populations and can be useful for health control, regular examination and pre-sale soundness examination.

• Journal of Internet Computing and Services
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• v.9 no.5
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• pp.85-97
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• 2008

Recently, service-oriented systems have been issued by their properties of reducing software development time and effort by reusing functional service units. The reusability of services can effectively promote through loose coupling between services and loose coupling between services depends on component-based system. That is, the component-based system is designed by grouping the tightly coupled classes of the object-oriented system and the service-oriented system is designed by the component-based system. Therefore, to design the component-based system and service-oriented system efficiently, a metric to measure the coupling between classes accurately needs. In this paper, we propose a coupling metric between classes applying a structural property, a dynamic property, and the normalized value by 0-1. We prove the theoretical soundness of the proposed metric by the axioms of briand et al, and suggest the accuracy and practicality through a case study. We suggest the evaluation results of the proposed metric through a comparison with the conventional metrics.

• The KIPS Transactions:PartB
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• v.15B no.2
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• pp.147-158
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• 2008

Fuzzy Cognitive Map (FCM) and Bayesian Belief Network (BBN) are two major frameworks for modeling, representing and reasoning about causal knowledge. Despite their extensive use in causal knowledge engineering, there is no reported work which compares their respective roles. This paper aims to fill the gap by providing a qualitative comparison of the two frameworks through a systematic analysis based on some inherent features of the frameworks. We proposed a set of comparison criteria which covers the entire process of causal knowledge engineering, including modeling, representation, and reasoning. These criteria are usability, expressiveness, reasoning capability, formality, and soundness. The results of comparison have revealed some important facts about the characteristics of FCM and BBN, which will help to determine how FCM and BBN should be used, with respect to each other, in causal knowledge engineering.

• Computers and Concrete
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• v.19 no.1
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• pp.59-68
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• 2017

This study focused on modeling the behavior of the compressive stress using the average strain and ultrasonic test results in concrete. Feed-forward backpropagation artificial neural network (ANN) models were used to compare four types of concrete mixtures with varying water cement ratio (WC), ordinary concrete (ORC) and concrete with short steel fiber-reinforcement (FRC). Sixteen (16) $150mm{\times}150mm{\times}150mm$ concrete cubes were used; each contained eighteen (18) data sets. Ultrasonic test with pitch-catch configuration was conducted at each loading state to record linear and nonlinear test response with multiple step loads. Statistical Spearman's rank correlation was used to reduce the input parameters. Different types of concrete produced similar top five input parameters that had high correlation to compressive stress: average strain (${\varepsilon}$), fundamental harmonic amplitude (A1), $2^{nd}$ harmonic amplitude (A2), $3^{rd}$ harmonic amplitude (A3), and peak to peak amplitude (PPA). Twenty-eight ANN models were trained, validated and tested. A model was chosen for each WC with the highest Pearson correlation coefficient (R) in testing, and the soundness of the behavior for the input parameters in relation to the compressive stress. The ANN model showed increasing WC produced delayed response to stress at initial stages, abruptly responding after 40%. This was due to the presence of more voids for high water cement ratio that activated Contact Acoustic Nonlinearity (CAN) at the latter stage of the loading path. FRC showed slow response to stress than ORC, indicating the resistance of short steel fiber that delayed stress increase against the loading path.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5460-5466
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• 2014

In this study, mainly for kitchen knives and small swords, cutlery, etc. STS420J2 used material used for the experiments. In order to cure the surface of the test piece after the rough grinding and fine grinding was performed in order polishing. Perform the surface hardening of STS420J2 local area by using a diode laser. The output of the laser diode and the feed rate to the process variable. Micro-hardness testing, microstructure testing, scanning electron microscope testing(SEM), the heat input to the analysis. After analyzing the experiment to compare the mechanical properties of the material. When using a diode laser to assess the soundness of the surface hardening. Accordingly, the process for deriving the optimum demonstrate the feasibility.