• Title/Summary/Keyword: Direct expansion

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Application of Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry (Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry의 활용)

  • Pil Seung KWON
    • Korean Journal of Clinical Laboratory Science
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    • v.55 no.4
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    • pp.244-252
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    • 2023
  • The timeliness and accuracy of test results are crucial factors for clinicians to decide and promptly administer effective and targeted antimicrobial therapy, especially in life-threatening infections or when vital organs and functions, such as sight, are at risk. Further research is needed to refine and optimize matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based assays to obtain accurate and reliable results in the shortest time possible. MALDI-TOF MS-based bacterial identification focuses primarily on techniques for isolating and purifying pathogens from clinical samples, the expansion of spectral libraries, and the upgrading of software. As technology advances, many MALDI-based microbial identification databases and systems have been licensed and put into clinical use. Nevertheless, it is still necessary to develop MALDI-TOF MS-based antimicrobial-resistance analysis for comprehensive clinical microbiology characterization. The important applications of MALDI-TOF MS in clinical research include specific application categories, common analytes, main methods, limitations, and solutions. In order to utilize clinical microbiology laboratories, it is essential to secure expertise through education and training of clinical laboratory scientists, and database construction and experience must be maximized. In the future, MALDI-TOF mass spectrometry is expected to be applied in various fields through the use of more powerful databases.

Optimal flammability and thermal buckling resistance of eco-friendly abaca fiber/ polypropylene/egg shell powder/halloysite nanotubes composites

  • Saeed Kamarian;Reza Barbaz-Isfahani;Thanh Mai Nguyen Tran;Jung-Il Song
    • Advances in nano research
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    • v.16 no.2
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    • pp.127-140
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    • 2024
  • Upon direct/indirect exposure to flame or heat, composite structures may burn or thermally buckle. This issue becomes more important in the natural fiber-based composite structures with higher flammability and lower mechanical properties. The main goal of the present study was to obtain an optimal eco-friendly composite system with low flammability and high thermal buckling resistance. The studied composite consisted of polypropylene (PP) and short abaca fiber (AF) with eggshell powder (ESP) and halloysite clay nanotubes (HNTs) additives. An optimal base composite, consisting of 30 wt.% AF and 70 wt.% PP, abbreviated as OAP, was initially introduced based on burning rate (BR) and the Young's modulus determined by horizontal burning test (HBT) and tensile test, respectively. The effects of adding ESP to the base composite were then investigated with the same experimental tests. The results indicated that though the BR significantly decreased with the increase of ESP content up to 6 wt.%, it had a very destructive influence on the stiffness of the composite. To compensate for the damaging effect of ESP, small amount of HNT was used. The performance of OAP composite with 6 wt.% ESP and 3 wt.% HNT (OAPEH) was explored by conducting HBT, cone calorimeter test (CCT) and tensile test. The experimental results indicated a 9~23 % reduction in almost all flammability parameters such as heat release rate (HRR), total heat released (THR), maximum average rate of heat emission (MARHE), total smoke released (TSR), total smoke production (TSP), and mass loss (ML) during combustion. Furthermore, the combination of 6 wt.% ESP and 3 wt.% HNT reduced the stiffness of OAP to an insignificant amount by maximum 3%. Moreover, the char residue analysis revealed the distinct differences in the formation of char between AF/PP and AF/PP/ESP/HNT composites. Afterward, dilatometry test was carried out to examine the coefficient of thermal expansion (CTE) of OAP and OAPEH samples. The obtained results showed that the CTE of OAPEH composite was about 18% less than that of OAP. Finally, a theoretical model was used based on first-order shear deformation theory (FSDT) to predict the critical bucking temperatures of the OAP and OAPEH composite plates. It was shown that in the absence of mechanical load, the critical buckling temperatures of OAPEH composite plates were higher than those of OAP composites, such that the difference between the buckling temperatures increased with the increase of thickness. On the contrary, the positive effect of CTE reduction on the buckling temperature decreased by raising the axial compressive mechanical load on the composite plates which can be assigned to the reduction of stiffness after the incorporation of ESP. The results of present study generally stated that a suitable combination of AF, PP, ESP, and HNT can result in a relatively optimal and environmentally friendly composite with proper flame and thermal buckling resistance with no significant decline in the stiffness.

Effect of renin inhibition on an experimental glomerulonephritis - a preliminary report (레닌 억제제가 실험적 사구체 콩팥염에 미치는 효과 - 예비 보고)

  • Kang, Ju-Hyung;Heo, Jae-Kyung;Lee, Young-Sook;Han, Ji-Young;Ha, Il-Soo
    • Clinical and Experimental Pediatrics
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    • v.52 no.8
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    • pp.938-943
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    • 2009
  • Purpose : We performed this study in order to investigate the effect of direct renin inhibition on an experimental animal model with nephrotoxic serum nephritis and tried to give useful information for clinical research and renin inhibitor treatment. Methods : Thirty BALB/c 6-week-old male mice were divided into 4 groups: control group (CO, n=5), control-treatment group with aliskiren (CT, n=5), disease group (DO, n=10), and disease treatment group with aliskiren (DT, n=10). Nephritis was induced by an intravenous injection of 0.25 mg/g weight of rabbit anti-GBM immunoglobulin G. Model 2002 Alzet mini-osmotic pumps (Durect Corp.) for aliskiren infusion were implanted into CT and DT. Each group strain was sacrificed serially one at a time on day 14. We estimated the protein-creatinine ratio in 12-hour-collected urine (UP/Cr) and measured the mesangial matrix score in the PAS-stained kidney of each strain. Results : One strain at CT and DT died on day 6 and 7, respectively. Each group strain was sacrificed serially at a time on day 10 because DO were seriously ill. The UP/Cr of each group is as follows: CO, $31.24{\pm}6.54mg/mg$, CT, $23.38{\pm}13.60mg/mg$, DO, $112.72{\pm}10.97mg/mg$, DT $114.07{\pm}32.30mg/mg$. There was no significant difference between DO and DT. The mesangial matrix score of each group was CO, $0.23{\pm}0.10$; CT, $0.13{\pm}0.03$; DO, $1.90{\pm}0.48$; and DT, $1.28{\pm}0.41$, respectively, and there was a significant difference between DO and DT in the extent of mesangial matrix expansion (P=0.008). Conclusion : We found that renin inhibition was able to suppress the mesangial matrix expansion in experimental mice with acute nephritis, although there were no significant differences in UP/Cr.

The Knowledge Transfer Network and Performance of Chinese Subsidiary in Korean MNCs : Focusing on Roles of Absorptive Capacity and Entry Mode (한국 다국적기업의 중국 자회사의 지식이전, 네트워크와 경영성과에 관한 연구 - 흡수능력과 진입방식의 역할을 중심으로 -)

  • Yoon, Ki-Chang
    • Korea Trade Review
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    • v.41 no.5
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    • pp.325-351
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    • 2016
  • This study empirically investigated the relationship among knowledge transfer, network(firm network and government network) and performance Korean MNCs' subsidiaries in terms of absorptive capacity and entry mode roles in China. For this, absorptive capacity was established as an independent variable, mediating variable, and moderating variable. And the entry mode was divided into single investment and joint venture and set to the moderating variable. Data for the analysis of actual proof was randomly selected from the companies which was established more than 3 years before KOTRA 'The overseas expansion Korean company directory (2014)'. Questionnaires to 138 Chinese subsidiaries of Korean MNCs were collected by FAX and E-mail. AMOS was utilized and collected data investigated the role of the absorption capacity and entry mode as the covariance structure analysis. The empirical analysis showed that absorption capacity has a direct influence on management performance as an independent variable with the network (firm network and government network). It only has a partial mediating role between enterprise networks and management performance, and no meaningful result was gained as its moderationg role bewteen the exogenous variable and management performance. And in terms of Korean companies' moderating role in entering China, they have a moderating role between government network, absorption capacity and management performance, but did not show a statistically significant result between knowledge transfer, enterprise network and management performance. Absorption capacity, as the variable affecting overseas subsidiary's management performance, should not be considered a mediating or moderating variable, but an independent variable. Since the joint venture is showing higher performance than single investment when going into the Chinese market, implication is provided for options in overseas expansion. But this research has the limitation in generalization because it is aiming at the subsidiaries of the Korean company investing in China. Therefore, it is more desirable in the future to conduct a study of the subsidiary of the Korean company entering several countries. It also has limitations in generalization, because the research was conducted using a limited number of variables, despite there are various factors affecting the management performance of Chinese subsidiaries.

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Research Framework for International Franchising (국제프랜차이징 연구요소 및 연구방향)

  • Kim, Ju-Young;Lim, Young-Kyun;Shim, Jae-Duck
    • 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.

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A Study on the Cooperative Marketing of Fishery Products in Korea (수협 마아케팅에 관한 연구)

  • 안세원
    • The Journal of Fisheries Business Administration
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    • v.17 no.1
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    • pp.77-106
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    • 1986
  • In the field of fisheries, there is at the apex Central Federation of Fishery Cooperatives, established under the Fishery Cooperatives Law(1962), It is a multipurpose organization with a membership of 105 cooperatives, 87 regional cooperatives, 15 business-type cooperatives and 3 manufactures' cooperatives. Accordingly, this thesis examines the marketing of fishery cooperatives in Korea, and in particular considers the marketing channel strategy of fisheries products. No company can perform by itself all the activities involved in the production and distribution of its products and services to its final markets. It must work with other firms to get the job done. Thus marketing channel firms of the fisheries products include primarily the fishery cooperatives, the licensed In the field of fisheries, there is at the apex Central Federation of Fishery Cooperatives, established under the Fishery Cooperatives Law (1962). It is a multipurpose organization with a membership of 105 cooperatives, 87 regional cooperatives, 15 business-type cooperatives and 3 manufactures' cooperatives. Accordingly, this thesis examines the marketing of fishery cooperatives in Korea, and in particular considers the marketing channel strategy of fisheries products. No company can perform by itself all the activities involved in the production and distribution of its products and services to its final markets. It must work with other firms to get the job done. Thus marketing channel firms of the fisheries products include primarily the fishery cooperatives, the licensed dealers and the merchant middlemen. The goal of marketing is in matching of segments of supply and demand. Every producer seeks to the link the marketing channel firms that will help it accomplish its objective best. This thesis tries to attempt to improve the present Korean Fishery Cooperatives marketing activities. The purpose of the operation of fishery cooperatives is to guarantee the profits of fisherman as well as the interests of general consumers by eliminating the inordinate profits of middlemen and by narrowing other market margins. Fishery cooperatives marketing activity functions forming a self-helf organization for economic protection of producers themselves, and acting as a market reformational institution through its transaction by group. The following are the characteristics of fishery cooperatives marketing. \circled1 Fishery cooperatives is organized with an economic factor and a personnel factor. \circled2 Fishery cooperatives is non-profit organization. \circled3 The members of fishery cooperatives is independent constitution of economy, but they are closely connected with the cooperative. \circled4 Fishery cooperatives is a mutual aid organization. The objective of an efficient marketing strategy may be well described by the common saying provides the right product at the right time, the right place, and the right price. But it is quite true that the Korean Fishermen's Cooperative can be said to owe its development to the successful implementation of the marketing system. The use of the marketing system has resulted in the following marketing strategy. 1. The direct marketing system. \circled1 The cooperation between the fishery cooperatives and the other cooperative through the collection and delivery center. \circled2 The selling between the fishery cooperatives and the large scale retailers through the process industry. 2. The vertical marketing system. \circled1The fishermen's cooperative to be nominated by wholesaler in the terminal market. \circled2 Contracted vertical marketing system. \circled3 Abolition of selling by double auction in the landing and the terminal market. 3. The physical distribution system. \circled1 The need for adoption of cold chain system to connect production directly to consumption. \circled2 The need for more expansion of landing markets and terminal market facilities. Solutions to the problems of the Korean fishery are made possible through effective functioning of cooperative marketing activities of fishery products. The marketing concept of fishermen's cooperative lies in the satisfaction of consumer needs. According to the marketing concept fishermen's cooperative should try to satisfy customer's needs through a coodinated set of activities that allows the organization to achieve its goal. Providing satisfaction to customers is the major trust of the marketing concept. To do this, a business must find out what will satisfy customers. With this information the cooperative sells to the greatest possible number of customers through the most efficient sales and marketing channels. Economic rationality of fishermen's cooperative marketing lies in reduction of marketing cost and elimination of intermediate institutions. Cooperative marketing and direct marketing are both indispensable marketing factors for a new cooperative organization among the manu ways. The cooperation between the fishermen's cooperative and the others cooperative, and vertical marketing system are the most necessary ones. Propulsion of cooperative marketing system could not be successful without the support of the marketing instituion's help. Consequently, successful cooperative marketing ought to lead to the necessity not only for the improvement of marketing organization, but for the application of a new marketing concept in the fishermen's cooperative.

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Effect on Digestion Efficiency by Adding Microbial Agent in Mesophilic Two-stage Anaerobic Digester (중온2단혐기성소화조에 미생물제재 주입시 소화효율에 미치는 영향)

  • Jung, Byung-Gil;Kim, Seok-Soon;Kang, Dong-Hyo;Sung, Nak-Chang;Choi, Seung-Ho;Lee, Hee-Pom
    • Journal of the Korea Organic Resources Recycling Association
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    • v.11 no.3
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    • pp.75-86
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    • 2003
  • In the near future, the capacity of conventional anaerobic digester is thought to be insufficient because of the increase of the total solids from expansion of intercepting sewer, sewage quantity and direct input of night soil from near apartment districts. The objectives of this study was to investigate the improvement of digestion efficiency using microbial agent(Bio-dh). The system was a pilot-scale, two-staged, anaerobic sludge digestion system. The first-stage digester was heated and mixed. The agitation velocity of the first-stage digester was 120rpm. The second-stage digester was neither heated nor mixed. The Digestion temperature was kept at $35{\pm}1^{\circ}C$ The detention time of digester was 19 days. The dosage of sewage sludge and microbial agent were $0.65m^3/day$ and $0.5{\ell}/day$, respectively. The experiments was run for 25days. Three times a week, $COD_{Mn}$ and SS of effluent, TS, VS, and biogas production rate were measured. Temperature, pH, and alkalinity were measured daily. The results were as follows ; Without microbial agent, digestion efficiencies ranged 46.0%~50.9%(mean=48.6%), with microbial agent(Bio-dh), digestion efficiencies ranged 52.8%~57.3%(mean=54.2%). Consequently, microbial agent(Bio-dh) increased the sludge digestion efficiency about 12%. Also, Without microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 1,639mg/L, 4,888mg/L respectively. With microbial agent, the mean concentration of $COD_{Mn}$ and SS of second-stage digester effluent were 859mg/L, 2,405mg/L respectively. Consequently, microbial agent(Bio-dh) increased the removal efficiency of $COD_{Mn}$ and SS about 47.6% and 50.8%, respectively.

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A Study On Changes in Cheong-gye-cheon & in Media Discourse: Based on Media Discoruse During 1960s, 1980s, and 2005 in Each Period (청계천 공간의 변화와 시기별 미디어 담론 변화에 대한 일 사례 고찰: 조선일보의 1960년대, 1980년대, 2005년 담론을 중심으로)

  • Kim, Byung-Wook;Eom, Jeong-Yoon;Kim, Seung-Hyun
    • Korean journal of communication and information
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    • v.51
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    • pp.26-46
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    • 2010
  • This study interprets Cheong-gye-cheon restoration as a process of space production during expansion of capitalism, and performs discourse analysis in order to find out that how media discourse has been related to the production of Cheong-gye-cheon space in each period of historical changes. This paper is particularly concentrating on discovering regulation in discourse which connects people's experiences and perception towards certain ways in the relationship between newly producted space and media discourse. This paper construes the period of 1960s as a process which pre-modern bodies and facilities were changed into modern and urban 'daily life' by practicing a space which splitted in a concept of time efficiency. In 1980s, media represented the facilities which had been constructed at the Cheong-gye-cheon space as a 'disqualified facilities for a center of the city'. This is because, tertiary industries were emerged at the 'Gang-nam' in this period which widen the gap of finance between 'Gang-nam' and 'Gang-Buk'. The government wanted to redevelop this space in order to function accumulating capital efficiently. Therefore shop owners nearby Cheong-gye-cheon were forced to move out. The discourse, 'disqualified facilities for a center of the city', implicates this process. The media discourse in the 2000s produced the 'myth' through the 'signifier' such as artificially flowing water, fine scenery, historical but artificial structure and etc.. However, people can experience symbols of the artificial structures which leads people to the luxurious restaurants, coffee shops, and etc.. Naturally, the spectacles produced by media direct people to the homogeneous pattern of consume. This phenomena can be explained as a process which people practice, intentionally or non-intentionally, the capitalistic mode of production which changed from a period of production to a period of consumption.

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A study of the relationship of the senior-guard's quality of exchange, job satisfaction and intention to leave one's job in private security company (민간경비업체에서 상사-부하 교환관계의 질, 직무만족 그리고 이직의도의 관계에 관한 연구)

  • Chung, Dae-Yong;Lee, Won-Haeng;Kim, Choon-Kwang
    • Korean Security Journal
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    • no.20
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    • pp.313-338
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    • 2009
  • Yet this study of a private security company guards who did not apply to most firms - An exchange relationship with the quality of the application of the theory of private security companies and the high turnover and low job satisfaction and find ways to improve the firm - An exchange relationship Job satisfaction and turnover of the quality of the major research variables with a theoretical discussion of the relationship they set and based on this study demonstrate the analysis is attempted. This expansion contributes to the possibility of applying the theory, and private security companies to manage their organizations more effective by presenting the theoretical basis. Was trying to contribute to practical. Therefore, in this study to determine the following three things that it first, in a private security company bosses - men exchange turnover of the members of the quality of the relationship is to help the relationship, secondly, from a private security company boss - An exchange relationship The quality of the work of the members are satisfied with the relationship, and finally the 'private security company's turnover in the member's job satisfaction is associated with a reduction of is whether. To this end, Seoul. Gyeonggi Province located in a private security guard companies and 238 people involved in the actual target and try to analyze these results demonstrate the firm - An exchange relationship to the quality of the turnover of the direct impact of the factors, but showed up as non - Job satisfaction showed a significant impact. Job satisfaction also significantly affect the turnover of the firm - An exchange relationship to the quality parameters according to degree of turnover. Therefore, exchange relationships with men from private security companies want to increase the quality of the firm's efforts to improve the men's job satisfaction indirectly through a reduction in turnover can be affected have been identified. We in the private security company to members of the firm's position in relation to their subordinates to improve the quality of the proposal is to.

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A Simulation-Based Investigation of an Advanced Traveler Information System with V2V in Urban Network (시뮬레이션기법을 통한 차량 간 통신을 이용한 첨단교통정보시스템의 효과 분석 (도시 도로망을 중심으로))

  • Kim, Hoe-Kyoung
    • Journal of Korean Society of Transportation
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    • v.29 no.5
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    • pp.121-138
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    • 2011
  • More affordable and available cutting-edge technologies (e.g., wireless vehicle communication) are regarded as a possible alternative to the fixed infrastructure-based traffic information system requiring the expensive infrastructure investments and mostly implemented in the uninterrupted freeway network with limited spatial system expansion. This paper develops an advanced decentralized traveler information System (ATIS) using vehicle-to-vehicle (V2V) communication system whose performance (drivers' travel time savings) are enhanced by three complementary functions (autonomous automatic incident detection algorithm, reliable sample size function, and driver behavior model) and evaluates it in the typical $6{\times}6$ urban grid network with non-recurrent traffic state (traffic incident) with the varying key parameters (traffic flow, communication radio range, and penetration ratio), employing the off-the-shelf microscopic simulation model (VISSIM) under the ideal vehicle communication environment. Simulation outputs indicate that as the three key parameters are increased more participating vehicles are involved for traffic data propagation in the less communication groups at the faster data dissemination speed. Also, participating vehicles saved their travel time by dynamically updating the up-to-date traffic states and searching for the new route. Focusing on the travel time difference of (instant) re-routing vehicles, lower traffic flow cases saved more time than higher traffic flow ones. This is because a relatively small number of vehicles in 300vph case re-route during the most system-efficient time period (the early time of the traffic incident) but more vehicles in 514vph case re-route during less system-efficient time period, even after the incident is resolved. Also, normally re-routings on the network-entering links saved more travel time than any other places inside the network except the case where the direct effect of traffic incident triggers vehicle re-routings during the effective incident time period and the location and direction of the incident link determines the spatial distribution of re-routing vehicles.