• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.4
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• pp.415-424
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• 2004

Cooling the electronic equipment is one of the major focal points of the design process and the key to successful product launch. The two-phase loop thermosyphone which is a good candidate among many available options was investigated fur cooling of the high power amplifiers. The system is composed of evaporator which contains 6 parallel cold plates, fan cooled condenser, gas-liquid separator, and interconnecting tubes. Experiments were performed for several refrigerant charging values, hs and as a experiment result, the optimum charging value fur this system was proposed. In order to optimize the system design, the operating cycle pressure and inlet/outlet temperatures of evaporator and condenser are measured and analyzed. The effect of the three parameters such as flow rate and temperature of condenser cooling air, and thermal load on the evaporator are investigated. The lower the operating pressure and the cycle temperatures are also better to prevent the leakage of the system. The system invesigated in this paper can be directly used for cooling of a real unmanned wireless communication station.

• Korean Management Science Review
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• v.32 no.1
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• pp.1-13
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• 2015

We estimate the option value embedded in reverse mortgages using the framework of European put option. The reverse mortgage is a very useful financial product for senior citizens who own homes but do not have a cash income while it is a high risk one from lender's perspective. One of benefits of the reverse mortgages is that the debt limit is restricted to the scope of the disposition price of the collateralized house, which is considered a put option to borrowers. The put option is evaluated using Black-Scholes model and a sensitive analysis is performed on variables such as discount rate, volatility, and time period. We confirm that the option value of reverse mortgages increases rapidly as the borrowers live longer than their life expectancy. The results of this study can be used to promote the reverse mortgage program more effectively in order to solve the problem of income shortage of the elderly homeowners.

• International Journal of Contents
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• v.11 no.1
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• pp.31-40
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• 2015

This paper primarily intends to explore whether smartphones accelerate the customer education paradox. Smartphone usage is becoming a mainstream habit, and it is changing people's shopping experience and conventional practices, hence presenting new challenges to the market. A smartphone affects customers strongly when they are trying to choose a product/service among a variety of options, and making purchase decisions. With smartphones bringing such changes and challenges to the market, especially to the companies and stores, it is important to understand market trends in order to retain the loyalty of existing customers as well as to attract new buyers. Therefore, companies and stores should offer enhanced and better technical service quality, along with the use of tools such as QR codes. Further, mobile based websites would offer a suitable approach in assisting customers using smartphones to obtain better information of greater value. The results of this study imply that there is an opportunity for organizations to design various methods of imparting customer education by using smartphones, such as loading applications on a smartphone that lead to more information with good quality and present real benefits regarding the products/services.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3
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• pp.237-244
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• 2002

In this paper we mention the optimization of MPEG-4 VM (Moving Picture Expert Group-4 Verification Model) GA (General Audio) AAC (Advanced Audio Coding) encoder and the design of the decoder for PDA (Personal Digital Assistant) using MPEG-4 VM source. We profiled the VMC source and several optimization methods have applied to those selected functions from the profiling. Intel Pentium III 600 MHz PC, which uses windows 98 as OS, takes about 20 times of encoding time compared to input sample running time, with additional options, and about 10 times without any option. Decoding time on PDA was over 35 seconds for the 17 seconds input sample. After optimization, the encoding time has reduced to 50% and the real time decoding has achieved on PDA.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.105-115
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• 2006

Thickness is a commonly used parameter in product design and manufacture. Its intuitive definition as the smallest dimension of a cross-section or the minimum distance between two opposite surfaces is ambiguous for intricate solids, and there is very little reported work in automatic computation of thickness. We present three generic definitions of thickness: interior thickness of points inside an object, exterior thickness for points on the object surface, and radiographic thickness along a view direction. Methods for computing and displaying the respective thickness values are also presented. The internal thickness distribution is obtained by peeling or successive skin removal, eventually revealing the object skeleton (similar to medial axis transformation). Another method involves radiographic scanning along a viewing direction, with minimum, maximum and total thickness options, displayed on the surface of the object. The algorithms have been implemented using an efficient voxel based representation that can handle up to one billion voxels (1000 per axis), coupled with a near-real time display scheme that uses a look-up table based on voxel neighborhood configurations. Three different types of intricate objects: industrial (press cylinder casting), sculpture (Ganesha idol), and medical (pelvic bone) were used for successfully testing the algorithms. The results are found to be useful for early evaluation of manufacturability and other lifecycle considerations.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.145-152
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• 2002

Real-time queueing information and/or predictive queue built-up information can be a good criterion in selecting travel options, such as routes, both for users, and for operators in operating transportation system. Provided properly, it will be a key information for reducing traffic congestion. Also, it helps drivers be able to select optimal roues and operators be able to manage the system effectively as a whole. To produce the predictive queue information, this paper proposes a predictive model for estimating and predicting queue lengths, mainly based on Kalman Filter. It has a structure of having state space model for predicting queue length which is set as observational variable. It has been applied for the Namsan first tunnel and the application results indicate that the model is quite reasonable in its efficacy and can be applicable for various ATIS system architecture. Some limitations and future research agenda have also been discussed.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.1631-1635
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• 2016

Helicobacter pylori infection plays an important role in the pathogenesis of chronic gastritis, peptic ulcer disease and gastric malignancy. A diagnosis of infection is thus an important part of a treatment strategy of many gastrointestinal tract diseases. Many diagnostic tests are available but all have some limitations in different clinical situations and laboratory settings. A single gold standard cannot available, but be used for diagnosis of Helicobacter pylori infection in daily clinical practice in all areas, so several techniques have been developed to give reliable results, especially focusing on real time endoscopic features. The narrow band imaging system (NBI) and high resolution endoscopy are imaging techniques for enhanced visualization of infected mucosa and premalignant gastric lesions. The aim of this article is to review the current diagnostic options and possible future developments detection of Helicobacter pylori infection.

• Journal of Korean Society for Geospatial Information Science
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• v.4 no.2 s.8
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• pp.173-180
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• 1996

In a grid based data transformation, the different gridding methods provide different interpretations of scattered data because each method calculate grid node values using a different weighted mathematical algorithms. Therefore, it is necessary to review the interpolated characteristics of some gridding methods according to search distance, search area and search options before determing the best method with a data set. For this, in this paper, six different gridding methods with the same search conditions are applied to a scattered data obtained from sterro-plotter. The interpolated characteristics of the scattered geographic data considered through comparison of coincidence between the data point and the grid node being interpolated. And also, shows the real application of gridding methods through calculating volumes and creating cross sections.

• Korean Medical Education Review
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• v.22 no.1
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• pp.16-27
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• 2020

The accreditation process (AccP) is both an opportunity and a burden for medical schools-which one it becomes depends on how medical schools recognize and utilize the AccP. In other words, if a medical school recognizes the AccP only as a formal procedure or as a means for continuing medical education, it will be a burden for the medical school. However, if a medical school recognizes the real and positive value of the AccP, it can be both an opportunity and a tool for developing medical education. The educational value of the AccP is to improve the quality, equity, and efficiency of medical education, along with increasing the options of choice. In order for the AccP to contribute to the development of medical education, accrediting agencies and medical schools must first be recognized as part of an "educational alliance" working together towards common goals. Secondly, clear guidelines on the accreditation standards should be periodically reviewed and shared. Finally, a formative evaluation using self-evaluation as a system that can utilize the AccP as an opportunity to develop medical education must be introduced. This type of evaluation system could be developed through collaboration among medical schools, academic societies for medical education, and the accrediting authority.

• East Asian Economic Review
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• v.22 no.2
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• pp.177-215
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• 2018

Trump's withdrawal from the Trans-Pacific Partnership (TPP) and his "America First" trade agenda ignite a second round of interest in mega-free trade agreements in the Asia-Pacific. Countries are evaluating alternative trade policy actions in a post-TPP era. Using national real GDP gains estimated by a modified GTAP model to construct "preference ordering" for 10 Association of Southeast Asian Nations members and their six regional dialogue partners, this paper comes up with several policy-oriented findings. First, when multilateral agreements are not possible, countries are better off with a regional trading agreement than without one. Second, the Regional Comprehensive Economic Partnership is likely to have higher beneficial impacts than the Comprehensive and Progressive Agreement for Trans-Pacific Partnership. Third, for dual-track countries, implementing both agreements is better than each separately. Fourth, impacts of open regionalism are likely to be higher than those of a closed and reciprocal one. Going forward, this paper argues that countries should adopt a "multi-track, multi-stage" approach to trade policy.