• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.113-122
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• 2017

This study was conducted to investigate the effect of dietary supplementation with Lactobacillus, medicinal plant extracts, and plant extracts on growth performance, cecal microflora, relative organ weight, and lymphocyte profile in broiler chickens. One hundred broilers (5 wk old) were used and divided into five (treatment) ${\times}$ two (challenged Salmonella) groups containing 10 broilers. The treatments were as follows: no antibiotics group (NC), antibiotics group (PC), 0.1% lactic acid bacteria group (LB), 100 ppm medicinal plant extract group (MPE), and 100 ppm herb extract group (HE). A basal diet was formulated as 3,100 kcal/kg ME and 20% CP based on corn and soybean meal. Broilers were fed with the experimental diets with no challenge for 1 wk and with challenge of SG for 2 wk. SG were added in water as $1.0{\times}10^6cfu/L$. Final body weight and weight gain were significantly decreased following challenge with SG (P<0.05). However, with the addition of antibiotic alternatives, growth performance was improved and reduction of performance following challenge with SG was lowed compared with that of the NC treatment (P<0.05). Coliform bacteria and Salmonella but not lactic acid bacteria increased with the addition of antibiotic alternatives (P<0.05). Lactobacillus increased significantly with the addition of lactic acid bacteria compared with the NC and PC treatments (P<0.05). The weight of liver, spleen, and bursa of Fabricius increased with addition of antibiotic alternatives (P<0.05). WBC was highly reduced at 4 days after challenge with SG, but was normally maintained thereafter. There was no significant difference in coliform bacteria, Salmonella, organ weights, or WBC with the addition of antibiotic alternatives. Finally, Lactobacillus, medicinal plant extract, and herb extract can be used as antibiotic alternatives; but one alternative completely can't alternate as antibiotics. Therefore, further studies are needed to investigate the synergistic effects of two or more antibiotic alternatives.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.12
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.

• The Journal of the Acoustical Society of Korea
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• v.37 no.4
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• pp.223-231
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• 2018

Recently, due to various environmental problems, blast tracks in tunnel are replaced with concrete tracks, but they have more adverse effects on noise than blast tracks so that additional noise measures are needed. Among these measures, sound-absorbing blocks start to be used due to its easy and quick installation. However, the performance of sound absorption blocks need to be verified under real environmental and operational conditions. In this paper, interior noise levels in KTX train cruising in Dalseong tunnel are measured before and after the installation of sound-absorbing blocks and the measured data are analyzed and compared. Additionally, noise reduction are estimated by modeling the high speed train, the tunnel and absorption blocks. Measurement devices and methods are used according to ISO 3381 and the equivalent sound pressure levels during the cruising time inside the tunnel are computed. In addition to overall SPLs(Sound Pressure Levels), 1/3-octave-band levels are also analyzed to account for the frequency characteristics of sound absorption and equipment noise in a cabin. In addition, to consider the effects of train cruising speeds and environmental conditions on the measurements, the measured data are corrected by using those measured during the train-passing through the tunnels located before and behind the Dalseong tunnel. Analysis of measured results showed that the maximum noise reduction of 6.8 dB (A) can be achieved for the local region where the sound-absorbing blocks are installed. Finally, through the comparison of predicted 1/3-octave band SPLs for the KTX interior noise with the measurements, the understanding of noise reduction mechanism due to sound-absorbing blocks is enhanced.

• Journal of Life Science
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• v.21 no.11
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• pp.1541-1548
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• 2011

This study was carried out to evaluate the effects of the addition of different levels of CFP (Cordyceps with fly pupa) on growth performance in broiler chickens. 400 broiler chicks (Ross 308, 1 day old) were sorted randomly into 4 treatment groups and fed experimental diets for 35 days. The treatment groups were divided into a control group not fed with CFP (T1), and treatment groups fed with CFP 2.0% (T2), CFP 3.5% (T3), and CFP 5.0% (T4). Although the broilers' weight gain and feed efficiency were significantly higher (p<0.05) in the T3 group throughout the entirety of the test period, no statistically significant differences were noted among the T1 and T2, T4 groups. Triglyceride in the blood, total cholesterol, and LDL-C were significantly lower in the CFP treatment groups than in the control group (p<0.05). The blood lipid reduction rate ranged from 5.32 to 10.63% for triglycerides, from 9.23 to 12.62% for total cholesterol, and from 44.67 to 53.81% for LDL-C in the CFP treatment groups relative to the control group. The abdominal fat weight ratio was reduced significantly in the CFP treatment groups (p<0.05) compared with the control group, with a reduction rate range of 17.67-21.68%. Broiler carcass weight, carcass rate, and ratios of breast muscle, skin and thigh muscle weights to carcass weight were significantly higher in the T3 group, and statistically significant differences were noted among the T1 and T2, T4 groups (p<0.05). Enteropathogenic E.coli and Salmonella were lower in the CFP treatment groups than in the control group, whereas the beneficial bacteria Bifidobacteria were significantly higher in the CFP treatment groups than in the control group (p<0.05). These findings suggest that the Cordyceps with fly pupa can improve the carcass characteristics and body weight gain in broiler chickens.

• Journal of Intelligence and Information Systems
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• v.26 no.1
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• pp.135-149
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• 2020

Artificial intelligences are changing world. Financial market is also not an exception. Robo-Advisor is actively being developed, making up the weakness of traditional asset allocation methods and replacing the parts that are difficult for the traditional methods. It makes automated investment decisions with artificial intelligence algorithms and is used with various asset allocation models such as mean-variance model, Black-Litterman model and risk parity model. Risk parity model is a typical risk-based asset allocation model which is focused on the volatility of assets. It avoids investment risk structurally. So it has stability in the management of large size fund and it has been widely used in financial field. XGBoost model is a parallel tree-boosting method. It is an optimized gradient boosting model designed to be highly efficient and flexible. It not only makes billions of examples in limited memory environments but is also very fast to learn compared to traditional boosting methods. It is frequently used in various fields of data analysis and has a lot of advantages. So in this study, we propose a new asset allocation model that combines risk parity model and XGBoost machine learning model. This model uses XGBoost to predict the risk of assets and applies the predictive risk to the process of covariance estimation. There are estimated errors between the estimation period and the actual investment period because the optimized asset allocation model estimates the proportion of investments based on historical data. these estimated errors adversely affect the optimized portfolio performance. This study aims to improve the stability and portfolio performance of the model by predicting the volatility of the next investment period and reducing estimated errors of optimized asset allocation model. As a result, it narrows the gap between theory and practice and proposes a more advanced asset allocation model. In this study, we used the Korean stock market price data for a total of 17 years from 2003 to 2019 for the empirical test of the suggested model. The data sets are specifically composed of energy, finance, IT, industrial, material, telecommunication, utility, consumer, health care and staple sectors. We accumulated the value of prediction using moving-window method by 1,000 in-sample and 20 out-of-sample, so we produced a total of 154 rebalancing back-testing results. We analyzed portfolio performance in terms of cumulative rate of return and got a lot of sample data because of long period results. Comparing with traditional risk parity model, this experiment recorded improvements in both cumulative yield and reduction of estimated errors. The total cumulative return is 45.748%, about 5% higher than that of risk parity model and also the estimated errors are reduced in 9 out of 10 industry sectors. The reduction of estimated errors increases stability of the model and makes it easy to apply in practical investment. The results of the experiment showed improvement of portfolio performance by reducing the estimated errors of the optimized asset allocation model. Many financial models and asset allocation models are limited in practical investment because of the most fundamental question of whether the past characteristics of assets will continue into the future in the changing financial market. However, this study not only takes advantage of traditional asset allocation models, but also supplements the limitations of traditional methods and increases stability by predicting the risks of assets with the latest algorithm. There are various studies on parametric estimation methods to reduce the estimated errors in the portfolio optimization. We also suggested a new method to reduce estimated errors in optimized asset allocation model using machine learning. So this study is meaningful in that it proposes an advanced artificial intelligence asset allocation model for the fast-developing financial markets.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.10
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• pp.1450-1459
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• 2001

These experiments were conducted to investigate the effects of different feeding and processing methods of diets on performance, morphological changes in the small intestine and nutrient digestibility of growing-finishing pigs. One-hundred fifty growing pigs ($Yorkshire{\times}Landrace{\times}Duroc$; initial body weight of $23.33{\pm}0.75kg$) and one-hundred twenty finishing pigs ($Yorkshire{\times}Landrace{\times}Duroc$; initial body weight of $59.22{\pm}0.56kg$) were used in Exp. 1 and Exp. 2, respectively. Pigs were grouped on the basis of body weight and gender, and randomly allotted into 6 different treatments with 5 replications in each treatment in a $2{\times}3$ factorial arrangement. Treatments were 1) dry feeding with a mash diet (DM), 2) dry feeding with a pelleted diet (DP), 3) dry feeding with an expanded crumble diet (DEC), 4) dry/wet feeding with a mash diet (WM), 5) dry/wet feeding with a pelleted diet (WP), and 6) dry/wet feeding with an expanded crumble diet (WEC). In Exp. 1 (growing phase), there was no significant difference in average daily gain (ADG) and average daily feed intake (ADFI) among treatments during the entire experimental period, but feed conversion ratio (FCR) was significantly (p<0.05) improved in pigs fed pelleted diets regardless of feeding method. FCR was best in pigs fed a DP diet and worst in pigs fed a WM diet. Pigs fed a pelleted diet showed a 6.2% or 4.0% improvement in FCR compared with those fed a mash diet or an expanded crumble diet. Water disappearance was not significantly affected by dry/wet feeding or feed processing. Significant differences in villus height were not found among treatments, but villus height tended to be improved by dry/wet feeding. Dry/wet feeding or feed processing did not affect crypt depth. Digestibilities of calcium and phosphorus were significantly (p<0.05) improved in pigs fed an expanded crumble diet compared with pigs fed mash diets. Especially, pigs fed a WEC diet digested 8.1% more P than those fed a DM diet. Feed cost per kg weight gain (FCG) tended to be increased by dry/wet feeding rather than dry feeding. In Exp. 2 (finishing phase), ADG and ADFI were not significantly different among treatments, but a significant difference in FCR was found among feed processing forms. The best FCR was obtained in pigs fed a pelleted diet. Pigs fed a DP diet showed a 11.3% improvement compared with those fed a DEC diet. Water disappearance was significantly (p=0.0408) decreased by feeding the mash diet. However, water disappearance was not affected by dry/wet feeding during the finishing period. The villus height and crypt depth were not significantly different among treatments. However, crypt depth tended to be decreased by dry/wet feeding at the mid part of the small intestine. Fat digestibility was improved by dry feeding rather than dry/wet feeding, and was improved by 4.8% by feeding pellet diets compared with expanded crumble diets. Except for carcass grade, carcass characteristics were not significantly (p<0.05) different among treatments. Carcass grade was the best in pigs fed a WP diet. Feed cost per kg weight gain (FCG) was significantly decreased in pigs fed a pelleted diet compared with those fed an expanded crumble diet, and tended to be decreased by dry/wet feeding. In conclusion, these studies suggest that feeding the pelleted diet to growing-finishing pigs can be beneficial in terms of FCR and production cost. Dry/wet feeding can be helpful for the maintenance of villus height, but may not be reflected in improved growth performance or reduction of production costs.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.421-433
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• 2023

The final disposal of spent nuclear fuel(SNF) from nuclear power plants takes place in a deep geological repository. The metal canister encasing the SNF is made of cast iron and copper, and is engineered to effectively isolate radioactive isotopes for a long period of time. The SNF is further shielded by a multi-barrier disposal system comprising both engineering and natural barriers. The deep disposal environment gradually changes to an anaerobic reducing environment. In this environment, sulfide is one of the most probable substances to induce corrosion of copper canister. Stress-corrosion cracking(SCC) triggered by sulfide can carry substantial implications for the integrity of the copper canister, potentially posing a significant threat to the long-term safety of the deep disposal repository. Sulfate can exist in various forms within the deep disposal environment or be introduced from the geosphere. Sulfate has the potential to be transformed into sulfide by sulfate-reducing bacteria(SRB), and this converted sulfide can contribute to the corrosion of the copper canister. Bentonite, which is considered as a potential material for buffering and backfilling, contains oxidized sulfate minerals such as gypsum(CaSO4). If there is sufficient space for microorganisms to thrive in the deep disposal environment and if electron donors such as organic carbon are adequately supplied, sulfate can be converted to sulfide through microbial activity. However, the majority of the sulfides generated in the deep disposal system or introduced from the geosphere will be intercepted by the buffer, with only a small amount reaching the metal canister. Pyrite, one of the potential sulfide minerals present in the deep disposal environment, can generate sulfates during the dissolution process, thereby contributing to the corrosion of the copper canister. However, the quantity of oxidation byproducts from pyrite is anticipated to be minimal due to its extremely low solubility. Moreover, the migration of these oxidized byproducts to the metal canister will be restricted by the low hydraulic conductivity of saturated bentonite. We have comprehensively analyzed and summarized key research cases related to the presence of sulfates, reduction processes, and the formation and behavior characteristics of sulfides and pyrite in the deep disposal environment. Our objective was to gain an understanding of the impact of sulfates and sulfides on the long-term safety of high-level radioactive waste disposal repository.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.1-8
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• 2014

Structures requiring chemical resistance are usually coated with surface protecting agents, but the cost for maintenance and re-construction is incurred due to the low durability. Therefore, in this study, sulfur was polymerized and the performance was examined so that it could be used as the concrete surface protecting agents for structures requiring chemical resistance. The evaluation results indicated that for the spray of the sulfur polymer surface coating agents, the application of the gravity type was appropriate; and for the number of coating times, about 3 cycle spray gave the best results. For the surface condition of the concrete to be coated with the surface protecting agents, outstanding quality was obtained above room temperature ($20{\sim}30^{\circ}C$), and the bond strength increased as the temperature increased. The evaluation results of the strength characteristics depending on the filler content of the surface protecting agents indicated that about 20~40% filler mixing contributed to the strength improvement as it reduced the shrinkage of the sulfur polymer. Also, the mixing of silica showed larger increase in the bond strength than the mixing of fly ash, and the most outstanding bond strength characteristics could be obtained by the mixing of both silica and fly ash. In the case of the chemical resistance, the strength reduction was minimized and outstanding chemical resistance was obtained when the fly ash and silica were substituted by 20%, respectively. The performance evaluation of the chloride ion penetration indicated that for the specimens coated with the sulfur polymer surface protecting agents, the chloride ion penetration resistance increased by 29~48% compared to the specimen without the coating of the surface protecting agent. The examination of the coating condition of the surface protecting agents, compressive strength, bond strength, chemical resistance, and salt damage resistance indicated that in the range of this study, the optimal level was when the silica and fly ash were substituted by 20%, respectively, as the filler for the sulfur polymer.

• Journal of Global Scholars of Marketing Science
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• v.18 no.4
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• pp.61-118
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• 2008

The purpose of this research is to construct research framework for international franchising based on existing literature and to identify research components in the framework. Franchise can be defined as management styles that allow franchisee use various management assets of franchisor in order to make or sell product or service. It can be divided into product distribution franchise that is designed to sell products and business format franchise that is designed for running it as business whatever its form is. International franchising can be defined as a way of internationalization of franchisor to foreign country by providing its business format or package to franchisee of host country. International franchising is growing fast for last four decades but academic research on this is quite limited. Especially in Korea, research about international franchising is carried out on by case study format with single case or empirical study format with survey based on domestic franchise theory. Therefore, this paper tries to review existing literature on international franchising research, providing research framework, and then stimulating new research on this field. International franchising research components include motives and environmental factors for decision of expanding to international franchising, entrance modes and development plan for international franchising, contracts and management strategy of international franchising, and various performance measures from different perspectives. First, motives of international franchising are fee collection from franchisee. Also it provides easier way to expanding to foreign country. The other motives including increase total sales volume, occupying better strategic position, getting quality resources, and improving efficiency. Environmental factors that facilitating international franchising encompasses economic condition, trend, and legal or political factors in host and/or home countries. In addition, control power and risk management capability of franchisor plays critical role in successful franchising contract. Final decision to enter foreign country via franchising is determined by numerous factors like history, size, growth, competitiveness, management system, bonding capability, industry characteristics of franchisor. After deciding to enter into foreign country, franchisor needs to set entrance modes of international franchising. Within contractual mode, there are master franchising and area developing franchising, licensing, direct franchising, and joint venture. Theories about entrance mode selection contain concepts of efficiency, knowledge-based approach, competence-based approach, agent theory, and governance cost. The next step after entrance decision is operation strategy. Operation strategy starts with selecting a target city and a target country for franchising. In order to finding, screening targets, franchisor needs to collect information about candidates. Critical information includes brand patent, commercial laws, regulations, market conditions, country risk, and industry analysis. After selecting a target city in target country, franchisor needs to select franchisee, in other word, partner. The first important criteria for selecting partners are financial credibility and capability, possession of real estate. And cultural similarity and knowledge about franchisor and/or home country are also recognized as critical criteria. The most important element in operating strategy is legal document between franchisor and franchisee with home and host countries. Terms and conditions in legal documents give objective information about characteristics of franchising agreement for academic research. Legal documents have definitions of terminology, territory and exclusivity, agreement of term, initial fee, continuing fees, clearing currency, and rights about sub-franchising. Also, legal documents could have terms about softer elements like training program and operation manual. And harder elements like law competent court and terms of expiration. Next element in operating strategy is about product and service. Especially for business format franchising, product/service deliverable, benefit communicators, system identifiers (architectural features), and format facilitators are listed for product/service strategic elements. Another important decision on product/service is standardization vs. customization. The rationale behind standardization is cost reduction, efficiency, consistency, image congruence, brand awareness, and competitiveness on price. Also standardization enables large scale R&D and innovative change in management style. Another element in operating strategy is control management. The simple way to control franchise contract is relying on legal terms, contractual control system. There are other control systems, administrative control system and ethical control system. Contractual control system is a coercive source of power, but franchisor usually doesn't want to use legal power since it doesn't help to build up positive relationship. Instead, self-regulation is widely used. Administrative control system uses control mechanism from ordinary work relationship. Its main component is supporting activities to franchisee and communication method. For example, franchisor provides advertising, training, manual, and delivery, then franchisee follows franchisor's direction. Another component is building franchisor's brand power. The last research element is performance factor of international franchising. Performance elements can be divided into franchisor's performance and franchisee's performance. The conceptual performance measures of franchisor are simple but not easy to obtain objectively. They are profit, sale, cost, experience, and brand power. The performance measures of franchisee are mostly about benefits of host country. They contain small business development, promotion of employment, introduction of new business model, and level up technology status. There are indirect benefits, like increase of tax, refinement of corporate citizenship, regional economic clustering, and improvement of international balance. In addition to those, host country gets socio-cultural change other than economic effects. It includes demographic change, social trend, customer value change, social communication, and social globalization. Sometimes it is called as westernization or McDonaldization of society. In addition, the paper reviews on theories that have been frequently applied to international franchising research, such as agent theory, resource-based view, transaction cost theory, organizational learning theory, and international expansion theories. Resource based theory is used in strategic decision based on resources, like decision about entrance and cooperation depending on resources of franchisee and franchisor. Transaction cost theory can be applied in determination of mutual trust or satisfaction of franchising players. Agent theory tries to explain strategic decision for reducing problem caused by utilizing agent, for example research on control system in franchising agreements. Organizational Learning theory is relatively new in franchising research. It assumes organization tries to maximize performance and learning of organization. In addition, Internalization theory advocates strategic decision of direct investment for removing inefficiency of market transaction and is applied in research on terms of contract. And oligopolistic competition theory is used to explain various entry modes for international expansion. Competency theory support strategic decision of utilizing key competitive advantage. Furthermore, research methodologies including qualitative and quantitative methodologies are suggested for more rigorous international franchising research. Quantitative research needs more real data other than survey data which is usually respondent's judgment. In order to verify theory more rigorously, research based on real data is essential. However, real quantitative data is quite hard to get. The qualitative research other than single case study is also highly recommended. Since international franchising has limited number of applications, scientific research based on grounded theory and ethnography study can be used. Scientific case study is differentiated with single case study on its data collection method and analysis method. The key concept is triangulation in measurement, logical coding and comparison. Finally, it provides overall research direction for international franchising after summarizing research trend in Korea. International franchising research in Korea has two different types, one is for studying Korean franchisor going overseas and the other is for Korean franchisee of foreign franchisor. Among research on Korean franchisor, two common patterns are observed. First of all, they usually deal with success story of one franchisor. The other common pattern is that they focus on same industry and country. Therefore, international franchise research needs to extend their focus to broader subjects with scientific research methodology as well as development of new theory.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.491-503
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• 2014

In this paper, a $TM_{31}$ higher order mode half circular-ring microstrip antenna with monopole-like radiation characteristic for on-body communication is proposed. By using shorting vias, $TM_{31}$ resonance mode was excited, while achieving compact low-profile antenna with monopole-like radiation characteristics. To overcome the narrow bandwidth of a patch antenna, a C-shape half ring patch with shorting vias having $TM_{31}$ mode is closely located around a half circular patch. For size reduction, half mode is adopted. The proposed antenna has the overall dimensions of $0.25{\lambda}_0{\times}0.46{\lambda}_0{\times}0.025{\lambda}_0$ at the industrial, scientific, and medical(ISM) 2.45 GHz band(2.4~2.485 GHz) and the 10-dB return loss is 4.24 % ranging from 2.38 to 2.49 GHz. To verify body effect, two-thirds muscle equivalent semi solid phantom was fabricated and used to measure the antenna performance. A communication link is analysed to investigate the effect of human-body movements and antenna locations.