• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.2
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• pp.1-17
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• 2015

In this paper, we propose a portfolio selection model utilizing a Markov chain for investing in the foreign exchange market based on market forecasts and exchange rate movement predictions. The proposed model is utilized to compute optimum investment portfolio weights for investing in margin-based markets such as the FX margin market. We further present an objective investment algorithm for applying the proposed model in real-life investments. Empirical performance of the proposed model and investment algorithm is evaluated by conducting an experiment in the FX market consisting of the 7 most traded currency pairs, for a period of 9 years, from the beginning of 2005 to the end of 2013. We compare performance with 1) the Dollar Index, 2) a 1/N Portfolio that invests the equal amount in the N target assets, and 3) the Barclay BTOP FX Index. Performance is compared in terms of cumulated returns and Sharpe ratios. The results suggest that the proposed model outperforms all benchmarks during the period of our experiment, for both performance measures. Even when compared in terms of pre- and post-financial crisis, the proposed model outperformed all other benchmarks, showing that the model based on objective data and mathematical optimization achieves superior performance empirically.

• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2594-2600
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• 2020

A gamma camera system using radionuclide has a functional imaging technique and is frequently used in the field of nuclear medicine. In the gamma camera, it is extremely important to improve the image quality to ensure accurate detection of diseases. In this study, we designed a blind-deconvolution framework after a noise-reduction algorithm based on a non-local mean, which has been shown to outperform conventional methodologies with regard to the gamma camera system. For this purpose, we performed a simulation using the Monte Carlo method and conducted an experiment. The image performance was evaluated by visual assessment and according to the intensity profile, and a quantitative evaluation using a normalized noise-power spectrum was performed on the acquired image and the blind-deconvolution image after noise reduction. The result indicates an improvement in image performance for gamma camera images when our proposed algorithm is used.

• Journal of Digital Convergence
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• v.13 no.11
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• pp.179-185
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• 2015

In this paper, we research the IPTV that is the convergence technique of TV and network technique and performed the performance evaluation of picture quality of IPTV in the situation of increasing the network traffic in the Internet environment. To do this, we constructed the mock Internet network similar to the real Internet environment and measured the quality of received video using V-Factor model according to the increase of network traffic, and analyzed the result of the experiment. Making use of the result of this paper for the threshold value of V-Factor, the measured factor of network performance, the measured factor of video performance in the watchable IPTV video quality.

• Journal of the Korea Society for Simulation
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• v.17 no.2
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• pp.31-47
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• 2008

As OWL(Web Ontology Language) has been selected as a standard ontology description language by W3C, many ontologies have been building and developing in OWL. The lena developed by HP as an Application Programming Interface(API) provides various APIs to develop inference engines as well as storages, and it is widely used for system development. However, the storage model of Jena2 stores most owl documents not acceptable into a single table and it shows low processing performance for a large ontology data set. Most of all, Jena2 storage model does not consider hierarchical structures of classes and properties. In addition, it shows low query processing performance using the hierarchical structure because of many join operations. To solve these issues, this paper proposes an OWL ontology relational database model. The proposed model semantically classifies and stores information such as classes, properties, and instances. It improves the query processing performance by managing hierarchical information in a separate table. This paper also describes the implementation and evaluation results. This paper also shows the experiment and evaluation result and the comparative analysis on both results. The experiment and evaluation show our proposal provides a prominent performance as against Jena2.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.5
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• pp.377-383
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• 2016

Recently, research on bone fracture and osteoplasty using ultrasonic bone surgery unit has been ongoing in the fields of dentistry, plastic surgery, and otorhinolaryngology. However, detailed data evaluation with ultrasonic bone surgery unit has not been conducted to date. In this study, we developed handpiece moving system (HMS) for cutting performance evaluation. In the experimental setup of HMS, a handpiece was immobilized, and bone samples from cortical bone of bovine leg were prepared. Also, the experimental process was described in detail, and a basic experiment was carried out to evaluate the cutting performance. Future study is required on all experimental process conditions by HMS.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.141-145
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• 2003

Step-by-step laboratory performance test and repetitive improvement of KRRI rail fastening system show that it has the similar capability as other fastening systems that have been globally used. In this study, for the evaluation of field applicability, construction and rolling-stock operation test of KRRI rail fastening system are performed. Through this approach, comparison against the service criteria of foreign countries are made.

• Proceedings of the ESK Conference
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• 1998.04a
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• pp.167-172
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• 1998

Methods of evaluating the physiological activity of the living body are EEG, EOG, Heart rate, and Rectal temperature, etc. In the study of Hagiwara and Araki(1993), they found positive correlations among performance test, physiological measurement, and subjective feeling measurement. Human alertness of pilot directly influences on the flight performance that accomplishes a lot of vigilance task and procedure execution in flight. Accordingly, this paper deals with the quantitative and objective performance test based on tracking error and reaction time by means of the new computer test program into which the perception-motion system of human beings is applies. Throughout this experiment using performance thst, the results suggest that performance capability in state of sleep deprivation 2 hours and alcoholic 0.05 .apaprox. 0.06% in blood were more impaired than one in a normal state, and they further showed statistically significant differences between them, which were influenced by impairment factors of body regulation and pilot's grade. We also obtained the prediction value and the 95% confidence interval of tracking error and reaction time at the normal state for the purpose of distinguishing performance capability between the normal state and the abnormal state. And it is ecpected that the evaluation of human alertness using performance test will be applied to the quantitative assessment of an each pilot's realistic consciousness/attention, and will lead a flight commander to the accurate decision of mission approval prior to a flight.

• Korean Journal of Digital Imaging in Medicine
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• v.11 no.2
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• pp.85-92
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• 2009

This study, "The study about performance evaluations of mobile cover for X-ray's diffusion and distribution in mobile radiation" is based on the rules of mobile defense apparatus for radiation producer in 2006. To use the mobile cover for X-ray for diagnosis has been compulsory in common wards except operation rooms, emergency rooms and intensive care units. we have confirmed the effect in arbitrary shielding material after Qualitiy Control was carried out for accuracy in an experiment of mobile photographing equipment. The performance evaluation was conducted with the fabrics of selenium, 0.2 mmPb, 0.1 mmPb and aluminiums. Considering the result, we choosed 0.1 mmPb and attached cover to mobile photographing equipment. We have finished making the cover after drew up the draft to attach cover to mobile photographing equipment through the modeling and the structural analysis. the process of the study is that we assembled the manufactured structures and carried out the practical experiment to take the photograph after attaching the fabric of 0.1 mmPb to mobile photographing equipment. It is need of additional thesises hereafter that we compare the result between the part to improve for safety besides convenience in photographic experiment about clinical radiation and the effect of covering the diffusion in condition attached the cover.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.70-75
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• 2001

There is a problem to be solved for improvement of durability and safety for concrete When the waterproofing and anticorrosive work of main concrete are design, the material a of construction need to be correctly applied to appropriate circumstance conditions. Epoxy mostly been used for concrete water tank structure. Lately, lots of subjects on adaption res in mortar for waterproofing and anticorrosive are under discussion. Then, we attempt to approach by evaluating and comparing every capabilities with waterproofing materials in this experiment. Capability evaluation items include the bond age and curing conditions, the bond strength after accelerated weathering test and fret impact resistance, a mount of water, seepage quan Through the experiment analysis, we found that waterproofingtity, drinking water chemicals resistance. and anticorrosive resin mortar used with glass fiber cloth, inorgar material is dominantly superior to other waterproofing materials. According to this paper, we suggest the resin mortar as a new surface treatment material water tank structure.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.577-584
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• 2023

In this study, among the parts of oil vapor collectors that are already being produced, weaving wire brush automatic transplanters for oil vapor collectors for machine tools of the weaving fixing method, which are not automated due to the specificity of the process and are being produced manually, are developed and reliability is secured through performance evaluation. did Oil vapor collectors play an important role in removing air pollutants and improving air quality, and the coagulation effect of the collection technology is mostly due to brushes. In the experiment, an automatic transplanter was developed to automatically manufacture and produce the wire brush of the oil vapor collector, which is manufactured and used manually. For the experiment of the developed wire brush, an experimental chamber was built, and performance and durability were evaluated through the dust collection efficiency evaluation using the electrostatic precipitator method of contaminants (oil mist). Through this study, we intend to reduce the production time and unit cost of collectors and improve the environment at industrial sites.