• Title/Summary/Keyword: Empirical Method

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The Properties of Beam Intensity Scanner (BInS) for Dose Verification in Intensity Modulated Radiation Therapy (방사선 세기 조절 치료에서 선량을 규명하는 데 사용된 BlnS System의 특성)

  • 박영우;박광열;박경란;권오현;이명희;이병용;지영훈;김근묵
    • Progress in Medical Physics
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    • v.15 no.1
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    • pp.1-8
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    • 2004
  • Patient dose verification is one of the most Important responsibilities of the physician in the treatment delivery of radiation therapy. For the task, it is necessary to use an accurate dosimeter that can verify the patient dose profile, and it is also necessary to determine the physical characteristics of beams used in intensity modulated radiation therapy (IMRT) The Beam Intensity Scanner (BInS) System is presented for the dosimetric verification of the two dimensional photon beam. The BInS has a scintillator, made of phosphor Terbium-doped Gadolinium Oxysulphide (Gd$_2$O$_2$S:Tb), to produce fluorescence from the irradiation of photon and electron beams. These fluoroscopic signals are collected and digitized by a digital video camera (DVC) and then processed by custom made software to express the relative dose profile in a 3 dimensional (3D) plot. As an application of the BInS, measurements related to IWRT are made and presented in this work. Using a static multileaf collimator (SMLC) technique, the intensity modulated beam (IMB) is delivered via a sequence of static portals made by controlled leaves. Thus, when static subfields are generated by a sequence of abutting portals, the penumbras and scattered photons of the delivered beams overlap in abutting field regions and this results in the creation of “hot spots”. Using the BInS, inter-step “hot spots” inherent in SMLC are measured and an empirical method to remove them is proposed. Another major MLC technique in IMRT, the dynamic multileaf collimator (DMLC) technique, has different characteristics from SMLC due to a different leaf operation mechanism during the irradiation of photon and electron beams. By using the BInS, the actual delivered doses by SMLC and DMLC techniques are measured and compared. Even if the planned dose to a target volume is equal in our experimental setting, the actual delivered dose by DMLC technique is measured to be larger by 14.8% than that by SMLC, and this is due to scattered photons and contaminant electrons at d$_{max}$.

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A Study on the Relationship Between the Performance of Venture Business and CEO's Characteristics (벤처기업 경영자 특성이 경영성과에 미치는 영향에 관한 연구;대덕연구개발특구를 중심으로)

  • Yoon, Bo-Hyun;Park, Joon-Byoung
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.2 no.3
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    • pp.145-168
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    • 2007
  • Current researches have been proceed on CEO's Characteristics of venture business because the CEO has considered as one of the important factors for the success of venture business. But prior research on the performance of venture business has produced inconsistently in terms of CEO's characteristics. The purpose of this study is to develop a comprehensive model for the relation between the performance and a type of CEO's characteristics by a growth process of venture business, which is the main subject of analysis in venture business. Also, this study analyzes various CEO's characteristics and the effects for performance of venture business which are in the Daedeok valley. To achieve the purpose of this research, an empirical study by using research model and hypotheses including the general characteristics of venture business and CEO's demographic characteristics has been presented as a research method for relation analysis. The principal findings of the research and its significance are summarized as follows: First, it was found that there is a significant different in the performance of CEO's behavioral characteristics by the scale, type and growing step of organization for venture business. Second, it was found that there is not a significant between an academic career, management experience, foundation experience for business and related working experience of venture CEO and the performance, but there os a partially significant difference in CEO's behavioral characteristics. Third, it was found that there is a partially significant difference between CEO's behavioral characteristics of venture business and the performance by the general characteristics of organization for venture business and demographic characteristics. In conclusion, in spite of the insufficient research for venture business in Daedeok, the implications of theses findings and contributions made by this research is to confirm the characteristics factor of CEO for venture business and general characteristics of organization for venture business by multidisciplinary side. In addition, the findings provide the basis for the analyzing of managerial strong point and weak point referred to supporting system for venture business. Finally, the findings of this study suggest that the results should be a useful data for groping a solution for upbringing plans in terms of a long-term point of view.

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A Resource-Based Perspective on Three IT Resources and Their Relationships in IT Outsourcing (IT 아웃소싱 성공에 영향을 미치는 3가지 IT 자원들과 그 관계: 자원기반 관점에서)

  • Kim, Chy Heon;Kim, Joon S.;Im, Kun Shin
    • Information Systems Review
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    • v.14 no.3
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    • pp.53-74
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    • 2012
  • IT outsourcing (ITO) is an integration of two firms-external vendor(s) and a client firm-IT resources by contract. According to resource-based view(RBV), three different resources-ITO vendor's resource, client firm's resource, and the relationship resource between two firms- may have an impact on ITO performance. However, there have been few previous studies considering all three IT resources simultaneously. There have been also few empirical studies in ITO context, which test Bharadwaj (2000)'s findings: 1) IT resources can be divided into tangible IT asset and intangible IT capability, and 2) only IT capability has an impact on the IT performance. Therefore we examined whether, in ITO context, all three different resources have a significant impact on ITO performance. Adopting the findings of previous IT studies, we also divided IT resource into IT asset and IT capability. To achieve this research objective, we analyzed 62 ITO cases of 45 companies being listed in Korean top 100 companies for recent 3 years. Also, we analyzed the data with the Partial Least Squares method. The results of this research lead to the following conclusions: First, only when partnership is high, ITO vendors' resource can have an influence on ITO performance. Second, only client firm's IT capability, not IT asset, is directly related to the ITO success. Third, a firm's IT capability can increase the partnership. Therefore, we concluded that 1) RBV is also an useful theory in ITO context, 2) Bharadwaj(2000)'s suggestion is valid in ITO context as well, and 3) the relationship resource is also important in ITO.

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The Adoption and Diffusion of Semantic Web Technology Innovation: Qualitative Research Approach (시맨틱 웹 기술혁신의 채택과 확산: 질적연구접근법)

  • Joo, Jae-Hun
    • Asia pacific journal of information systems
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    • v.19 no.1
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    • pp.33-62
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    • 2009
  • Internet computing is a disruptive IT innovation. Semantic Web can be considered as an IT innovation because the Semantic Web technology possesses the potential to reduce information overload and enable semantic integration, using capabilities such as semantics and machine-processability. How should organizations adopt the Semantic Web? What factors affect the adoption and diffusion of Semantic Web innovation? Most studies on adoption and diffusion of innovation use empirical analysis as a quantitative research methodology in the post-implementation stage. There is criticism that the positivist requiring theoretical rigor can sacrifice relevance to practice. Rapid advances in technology require studies relevant to practice. In particular, it is realistically impossible to conduct quantitative approach for factors affecting adoption of the Semantic Web because the Semantic Web is in its infancy. However, in an early stage of introduction of the Semantic Web, it is necessary to give a model and some guidelines and for adoption and diffusion of the technology innovation to practitioners and researchers. Thus, the purpose of this study is to present a model of adoption and diffusion of the Semantic Web and to offer propositions as guidelines for successful adoption through a qualitative research method including multiple case studies and in-depth interviews. The researcher conducted interviews with 15 people based on face-to face and 2 interviews by telephone and e-mail to collect data to saturate the categories. Nine interviews including 2 telephone interviews were from nine user organizations adopting the technology innovation and the others were from three supply organizations. Semi-structured interviews were used to collect data. The interviews were recorded on digital voice recorder memory and subsequently transcribed verbatim. 196 pages of transcripts were obtained from about 12 hours interviews. Triangulation of evidence was achieved by examining each organization website and various documents, such as brochures and white papers. The researcher read the transcripts several times and underlined core words, phrases, or sentences. Then, data analysis used the procedure of open coding, in which the researcher forms initial categories of information about the phenomenon being studied by segmenting information. QSR NVivo version 8.0 was used to categorize sentences including similar concepts. 47 categories derived from interview data were grouped into 21 categories from which six factors were named. Five factors affecting adoption of the Semantic Web were identified. The first factor is demand pull including requirements for improving search and integration services of the existing systems and for creating new services. Second, environmental conduciveness, reference models, uncertainty, technology maturity, potential business value, government sponsorship programs, promising prospects for technology demand, complexity and trialability affect the adoption of the Semantic Web from the perspective of technology push. Third, absorptive capacity is an important role of the adoption. Fourth, suppler's competence includes communication with and training for users, and absorptive capacity of supply organization. Fifth, over-expectance which results in the gap between user's expectation level and perceived benefits has a negative impact on the adoption of the Semantic Web. Finally, the factor including critical mass of ontology, budget. visible effects is identified as a determinant affecting routinization and infusion. The researcher suggested a model of adoption and diffusion of the Semantic Web, representing relationships between six factors and adoption/diffusion as dependent variables. Six propositions are derived from the adoption/diffusion model to offer some guidelines to practitioners and a research model to further studies. Proposition 1 : Demand pull has an influence on the adoption of the Semantic Web. Proposition 1-1 : The stronger the degree of requirements for improving existing services, the more successfully the Semantic Web is adopted. Proposition 1-2 : The stronger the degree of requirements for new services, the more successfully the Semantic Web is adopted. Proposition 2 : Technology push has an influence on the adoption of the Semantic Web. Proposition 2-1 : From the perceptive of user organizations, the technology push forces such as environmental conduciveness, reference models, potential business value, and government sponsorship programs have a positive impact on the adoption of the Semantic Web while uncertainty and lower technology maturity have a negative impact on its adoption. Proposition 2-2 : From the perceptive of suppliers, the technology push forces such as environmental conduciveness, reference models, potential business value, government sponsorship programs, and promising prospects for technology demand have a positive impact on the adoption of the Semantic Web while uncertainty, lower technology maturity, complexity and lower trialability have a negative impact on its adoption. Proposition 3 : The absorptive capacities such as organizational formal support systems, officer's or manager's competency analyzing technology characteristics, their passion or willingness, and top management support are positively associated with successful adoption of the Semantic Web innovation from the perceptive of user organizations. Proposition 4 : Supplier's competence has a positive impact on the absorptive capacities of user organizations and technology push forces. Proposition 5 : The greater the gap of expectation between users and suppliers, the later the Semantic Web is adopted. Proposition 6 : The post-adoption activities such as budget allocation, reaching critical mass, and sharing ontology to offer sustainable services are positively associated with successful routinization and infusion of the Semantic Web innovation from the perceptive of user organizations.

Analysis of Water Relations of Economic Oak Species by Hydraulic Architecture Method (Hydraulic architecture를 이용한 참나무속 주요 수종의 수분 특성 분석)

  • Kwon, Ki Won;Choi, Jeong Ho;Kim, Sun Ah
    • Korean Journal of Agricultural Science
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    • v.23 no.1
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    • pp.108-119
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    • 1996
  • Several parameters of hydraulic architecture relating to hydraulic conductance in xylem vessels were investigated in the current-year shoots of six species of deciduous oak trees. The above parameters were also investigated in the sprouts of Quercus mongolica and Q. variabilis, as well as in the seedlings of Q. mongolica and Q. acutissima. The values of specific conductivity, leaf specific conductivity and Hagen-Poiseuille's relative hydraulic conductivity relating to vessel diameter of Q. dentata were the highest in all of the species studied. The above values of most of the species studied were higher in May-June than in September-October because of increasing the vessel embolism by cavitation and so on through the growing season. The estimated values of relative hydraulic conductivity of vessel by Hagen-Poiseuille's empirical equation and the real values of hydraulic conductivity presented positive relationships in most of the species studied. Huber value and leaf specific conductity using leaf area or leaf weight generally exhibited similar patterns each other even if having some exceptions. The hydraulic conductances of sprouting shoots were much better than those of normal growing shoots in Q. rnongolica and Q. variabilis. The specific conductivity and leaf specific conductivity were rapidly decreased by the vessel embolism through cavitating just after cutting the shoots in Q. mongolica and Q. acutissima seedlings. Diurnal changes of the conductivities in the seedlings of Q. mongolica and Q. acutissima presented the possibility of their self-controlling of conductance by active moisture absorption under mild water stress. Specific conductivity and leaf specific conductivity, and so on of Q. acutissima seedlings subjected to periodical moisture stress or not have decreased through the growing season, but the influences of moisture stress to the conductance were not proved definitely because of influencing similarly and simultaneously to the development of xylem and leaf having inverse relation in the influences. The values of conductivities were higher generally in middle or upper parts of stems than root collar in the seedlings.

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A Study on awareness of environmental management Knowledge and enviromental management behavior of Housewives (주부의 환경관리지식 인지도와 환경관리행동에 관한 연구)

  • 노남숙
    • Hwankyungkyoyuk
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    • v.7 no.1
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    • pp.106-122
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    • 1994
  • The purpose of this study to investigate the awareness of environmental management knowledge and behavior and the effect of independent variables (The environmental management behavior of housewives are composed of five activities-clothing, eating, housing, buying, family management. The independent variables are composed of objective variable and subjective variable). The Research Questions are as follows; 1. Are there significant differences in the housewife's awareness of the environmental management knowledge according to the objective variable and the subjective variable? 2. How much are the effects of related variables on the awareness of environmental management knowledge? 3. Are there significant differences in the housewife's environmental management behavior according to objective variable and subjective variable and awareness of environmental management knowledge? 4. How much are effects of related variables on the housewife's environmental management behavior? For these purpose, a theoretical framework was developed by literature review and applied to empirical test. The data was collected through the questionnaire those respondents were 477 housewives in seoul. It was analyzed by various statistical methods such as Frequency. Percentile, GLM, F-test, T-test, Duncan's Multiple Range Test, Pearson's Correlations Analysis Simple Regression Analysis, and Multiple Regression Analysis. The results of this research are as follows; 1. The awareness of environmental management knowledge had significant differences according to the variables such as housewife's age, husband's job, family number, education experience of environment, frequencies of contracting mass media, the perceived adequacy of resources, social-altruistic orientation. 2. Among all of these variables affecting the awareness of environmental management knowledge, the perceived adequacy of resources had the highest effects and the next were family number, social-altruistic, type of residence in order. 3. Total Environmental management behavior of housewives had significant differences according to the variables such of environment, frequencies of contracting mass media, the satisfaction of household labor, the perceived adequacy of resources, biospheric orientation, social-altruistic orientation, egoism orientation, the awareness of environmental management knowledge. The clothing, eating, housing, family management behavior had the high level, the buying management behavior had the average level. The clothing, eating, housing, buying, family management behavior had significant differences according to the variables such as the satisfaction of household labor, the perceived adequacy of resources, biospheric orientation, social-altruistic orientation, egoism orientation, the awareness of environmental management knowledge. In particular, the clothing, eating, housing, buying management behavior had significant differences according to the variables such as education experience of environment. And the housing, buying management behavior had significant differences according to the variables such as frequencies of contracting mass media. 4. Among all of theses variables affecting environmental management behavior, the most influence variables was awareness of environmental management knowledge and the next were influence of housewife's job, biospheric orientation, the satisfaction of household labor, education experience of environment, frequencies of contraction mass media, egoism orientation in order. Among all of theses variables effecting the clothing, eating, housing, buying management behavior the variables affecting the family management behavior, the most influences variables was housewife's job. In the result of analysing the housewife's environmental management behavior and awareness of environmental management knowledge, influences of education experience of environment had the highest effect and frequencies of contracting mass media may more influencial than other variables. And Concrete and systematic knowledge and technique of environmental education is requisite. The result of this study could be attributed to develop the efficient environmental information. More emphasis should be given to environmental education and a long range environmental policy. in particular, environmental education be effectively related to environmental behavior, life-education and systematic support must be provided. In addition, further study of environmental problem is needed for and application of various theoretical approaches and research method.

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Prediction of Seabed Topography Change Due to Construction of Offshore Wind Power Structures in the West-Southern Sea of Korea (서남해에서 해상풍력구조물의 건설에 의한 해저지형의 변화예측)

  • Jeong, Seung Myung;Kwon, Kyung Hwan;Lee, Jong Sup;Park, Il Heum
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.31 no.6
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    • pp.423-433
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    • 2019
  • In order to predict the seabed topography change due to the construction of offshore wind power structures in the west-southern sea of Korea, field observations for tides, tidal currents, suspended sediment concentrations and seabed sediments were carried out at the same time. These data could be used for numerical simulation. In numerical experiments, the empirical constants for the suspended sediment flux were determined by the trial and error method. When a concentration distribution factor was 0.1 and a proportional constant was 0.05 in the suspended sediment equilibrium concentration formulae, the calculated suspended sediment concentrations were reasonably similar with the observed ones. Also, it was appropriate for the open boundary conditions of the suspended sediment when the south-east boundary corner was 11.0 times, the south-west was 0.5 times, the westnorth 1.0 times, the north-west was 1.0 times and the north-east was 1.0 times, respectively, using the time series of the observed suspended sediment concentrations. In this case, the depth change was smooth and not intermittent around the open boundaries. From these calibrations, the annual water depth change before and after construction of the offshore wind power structures was shown under 1 cm. The reason was that the used numerical model for the large scale grid could not reproduce a local scour phenomenon and they showed almost no significant velocity change over ± 2 cm/s because the jacket structures with small size diameter, about 1 m, were a water-permeable. Therefore, it was natural that there was a slight change on seabed topography in the study area.

A Study on Ways of Promoting Design Management in Domestic Small and Medium Businesses (국내 중소기업의 디자인경영 활성화 방안에 관한 연구)

  • Lee, Soo-Bong
    • Archives of design research
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    • v.17 no.4
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    • pp.177-190
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    • 2004
  • The purpose of this study is to provide domestic small and medium manufacturing businesses with effective ways of introducing and promoting design management, earnestly, as a key strategy for raising corporate competitiveness. For the purpose, this researcher discussed the management property of small and medium businesses, the introducing process and method and the necessity of promoting design management in small and medium businesses. Then the researcher reviewed and analyzed existing empirical studies to know the current status of design introduction and design management promotion i domestic small and medium businesses. Results of the study can be described as below. Prerequisite to the successful introduction by domestic small and medium businesses of design management are three CEO determinations - the firm will to the necessity of design introduction, the firm conviction in design efficacy, and the clear recognition of the existential value of design - and the establishment of at least five infrastructures -design organization, CDO, designers, design policy, and design strategy. For the promoting and succeeding in the execution of design management, design management system should have established based on such determinations and infrastructures, and CEOs should have design management mind firmly established and driven and realized next activities in the process of product development. 1) Set the principle of design priority in a new product development and establish an appropriate production system and environment. 2) Decide a new design development as the top-priority task of management and then practice it in a strategic way. 3) Be positive in design investment while accepting design management as a concept related not to cost, but to investment. 4) Utilize design extensively under the understanding that design management has something to do with corporate design system as a whole. 5) Treat design as the most valuable resource of business under the recognition that design is the most important determinant of corporate competitiveness.

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The Influence of Private Health Insurance on Admission among Some Patients with Cervical or Lumbar Sprain (민영의료보험 가입이 일부 경·요추부 염좌 환자의 입원에 미치는 영향)

  • Jang, Dong-Ryul;Kang, Myung-Geun
    • Journal of agricultural medicine and community health
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    • v.37 no.2
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    • pp.84-95
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    • 2012
  • Background: In Korea, private health insurance has neglected to induce externality on national health insurance by moral hazard. Therefore, we conducted this study in order to explore the influence of private health insurance on unnecessary medical utilization among patients with cervical or lumbar sprain. Method: The study examined a population of 449 patients (admission, 384; out-patient; 85) diagnosed with simple cervical or lumbar sprain without neurological symptoms at 20 small hospitals or clinics in Gwangju and Jeollanam provinces from Jul. 1 to Aug. 31 2008. The data were collected using structured, self-administrated questionnaire which collected information such as whether or not the patient was admitted (as a dependent variable), whether or not they had private health insurance (as a independent variable), and covariates such as socio-demographic characteristics, the factors related to the sprain, and characteristics of the insurance provider. Results: From hierarchical multiple logistic regression analysis, it was found that the admission rate of patient with private health insurance was higher than that those without it (Odds ratio=3.31, 95% Confidence interval; 1.14-9.58), meaning that private health insurance was an independent factor influencing the admission of patients with these conditions. Other determinants of admission were patient age and physician referral. Conclusions: This study is the first empirical study to explore the influence of private health insurance on inducing moral hazard in admission services, specifically among patients with cervical or lumbar sprain. Regulation of benefits provided by private health insurance may be necessary, as the effect of this moral hazard may mean existence of externality.

The Effect of Social Network on Information Sharing in Franchise System (프랜차이즈시스템의 사회연결망 특성이 정보공유에 미치는 영향)

  • Yun, Han-Sung;Bae, Sang-Wook;Noh, Jung-Koo
    • Journal of Distribution Research
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    • v.16 no.2
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    • pp.95-118
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    • 2011
  • The purpose of this study is as follows. First, we investigate empirically the effects of social network properties such as social network density and centrality of a franchisee on its information sharing with various subjects such as the franchisor and other franchisees in the franchise system. Second, we examine exploratively if tie strength between a franchisee and its franchisor plays a moderating role on the relationship between social network properties and information sharing. The study model was established as shown in

    . We gathered 200 data from franchisees in Busan through a questionnaire survey and used 189 data for our purpose. To improve the quality of data, we selected respondents from the franchisees' owners or managers that had contacted often with their franchisor and other franchisees in the franchise system. Our data analysis began with reliability analysis, exploratory and confirmatory factor analysis, on the multi-item measures of social network density, social network centrality, tie strength, information sharing and control variables such as shared goals and ownership to assess the reliability and validity of those measures. The results were shown that the presented values satisfied the general criteria for reliability and validity. We tested our hypotheses using a hierarchical multiple regression analysis in four steps. Model 1 regressed the dependent variable(information sharing) only on control variables(shared goals, ownership). Model 2 added main effect variables(social network density, social network centrality) in Model 1. Model 3 added a moderating variable(tie strength) in Model 2. Finally, Model 4 added interaction terms between the main variables and the moderating variable in Model 3. We used a mean-centering method for the main variables and the moderating variable to minimize the multicollinearity problem due to the interaction terms in Model 4. Two important empirical findings emerge from this study. In other words, the effects of social network properties and tie strength on a franchisee's information sharing depend on subject types such as the franchisor and other franchisees in franchise system. First, social network centrality, tie strength, the interaction between social network density and tie strength and the interaction between social network centrality and tie strength all affect significantly a franchisee's information sharing with its franchisor. By the way, the interaction between social network centrality and tie strength has a negative effect on its information sharing while the interaction of social network density and tie strength has a positive effect on its information sharing. Second, both social network centrality affects significantly and directly a franchisee's information sharing with other franchisees in the franchise system. However, there does not exist the moderating role of tie strength in the second case. Finally, we suggest the implications of our findings and some avenues for future research.

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