• Title/Summary/Keyword: negative binomial

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The Study on the Performance and Determinants of Product Innovation in Machinery Industry (기계산업의 제품혁신 성과 및 결정요인에 관한 연구)

  • Bong, Kang Ho;Park, June Young;Park, Jaemin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.9
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    • pp.427-434
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    • 2018
  • As noted by Pavitt (1984) and Malerbar (2002), previous studies have focused on identifying differences in industry characteristics between the machinery industry and other manufacturing industries. This study considered quantitative and qualitative aspects of performance of product innovation in analyzing what factors determine those outcomes. In particular, this study examined stepwise selection processes embedded in innovation activities by applying a hurdle negative binomial model as well as the Heckman two-step selection model. Results show that factors affecting performance improvement and patents differ, and the threshold effect and the intensity effect of innovation were also distinguished. These results imply that the R&D capability should be enhanced and external innovation is required to be effectively embodied in the organization. Furthermore, motivating employees plays a pivotal role in this technology and skill-intensive sector.

Analyzing the Influence of Policy Measures for Growth Management Plan (성장관리방안 정책수단의 영향력 분석)

  • Jeon, Byung-Chang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.3
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    • pp.253-268
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    • 2020
  • This study examined the effectiveness of policy measures in a growth management plan by analyzing empirically the influence of regulations and incentives in a non-urban growth management plan of Sejong City using the binomial logistic model. The parcel unit data related development location of Sejong City from 2012 to 2017 was used in the model. The analysis showed that time regulation in the growth management plan has a negative (-) impact on the spread of development, which means it is effective in slowing urban sprawl by lowering the profits of developers. The time regulation applied in Sejong City needs to be used actively in other cities in Korea to prevent urban sprawl. Nevertheless, floor ratio incentives had no influence in inducing development within the growth management area, which means a new incentive policy to meet the local characteristics is needed to strengthen the effectiveness of the growth management plan. This study is meaningful because it attempted an empirical analysis of the effects of the growth management plan at The National Territory Act, and this study could encourage further studies.

A Study on Improvement of Design Method for Freeway Diverging Areas (고속도로 분류부 설계기법 개선 연구)

  • Park, Jae-Beom;Lee, Seung-Jun;Gang, Jeong-Gyu;Kim, Il-Hwan
    • Journal of Korean Society of Transportation
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    • v.25 no.1 s.94
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    • pp.23-35
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    • 2007
  • Freeway diverging areas are very vulnerable to traffic accidents due to abrupt vehicle speed changes and geometric changes. Therefore, in designing diverging areas, much attention should be Paid to safety The Present design criteria about freeway diverging areas regulate transition sections for lane changes, deceleration lanes, transition corves for direction changes. and other similar items. However, the design criteria were often violated in implementation because of ambiguities in the criteria. This study aims at clarifying and improving the present design criteria for freeway diverging areas. For this, field survey data and traffic accident data for diverging areas were analyzed.

Determinants of Inventor Productivity: An Empirical Result from Panel Regressions Using Network Characteristics (발명자 생산성 결정요인: 네트워크 특성을 이용한 패널회귀분석결과)

  • Choo, Kineung
    • Journal of Technology Innovation
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    • v.25 no.3
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    • pp.83-113
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    • 2017
  • This paper constructs panel data of inventors listed on patents applied for the KIPO during 1991-2005 and analyzes the effects of network characteristics on inventor productivity. The findings are as follows: ⅰ) Strong ties within a network have positive effects on inventor productivity. ⅱ) An inventor with high centrality shows high producitivity. ⅲ) Technological diversity of a network enhances inventor productivity. ⅳ) An inventor belonging to a network of good quality shows higher productivity. ⅴ) Network size is positively related with inventor producitvity. ⅵ) A lone inventor shows the highest productivity among types of inventors, and a co-inventor with the experience of standalone invention is more productive compared to an inventor with only the experience of co-invention. ⅶ) The productivity effects of network variables differ across regions. ⅷ) Differences among regions do not decrease though geographical boundaries become less important.

Analysis of Bicycle Accidents in Korea Based on Regional Characteristics (지역 특성을 고려한 국내 자전거 사고 분석)

  • KIM, Tae Yang;PARK, Byung Ho
    • Journal of Korean Society of Transportation
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    • v.35 no.5
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    • pp.447-457
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    • 2017
  • This study aims to analyze the accidents of green mode bicycle. In pursuing the above, this study gave special emphasis on modeling the bicycle accidents reflecting the regional characteristics. The main results are as follows. First, the null hypotheses that the number of accident and ratio of serious injury and fatality (FSI) were the same over regions were rejected. Second, as the common variables, the number of bicycle was judged to have positive (+) impact to the accidents and the bicycle using ratio was inferred to increase the ratio of FSI. Third, the elderly population ratio among 3 factors which gave impact to the accidents of Si_A (city-county consolidation) was concluded to have the greatest elasticity. The developed area ratio between 2 factors in Si_B (city which is not consolidated) was, however, estimated to have the higher elasticity. Fourth, the number of car registration among 5 accident factors of Gun (county) was analyzed to have the greatest elasticity. Finally, the commuting trip ratio among 7 accident factors of Gu (district) was judged to have the greatest elasticity. This study can be expected to give some implications to regional policy-making related to bicycle.

Association between Long Working Hours and Depressive Symptoms among Interns and Residents in South Korea-2014 Korea Interns & Residents Survey (전공의들의 장시간 근무와 우울증상의 연관성에 관한 연구)

  • Kim, Ji-Hwan;Yoon, Jaehong;Kim, Seung-Sup
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.25 no.2
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    • pp.236-243
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    • 2015
  • Objectives: This study sought to examine the association between long working hours and depressive symptoms among interns and residents in South Korea. Methods: We analyzed a cross-sectional survey of 1,661 interns and residents from the 2014 Korean Interns & Residents Survey. Total working hours during the preceding week was assessed and classified into five categories(i.e. less than 60 hours, 60-79 hours, 80-99 hours, 100-119 hours, and 120-168 hours). Depressive symptoms during the previous week were measured by using ten items from the Center for Epidemiologic Studies Depression Scale questionnaire. Multivariate negative binomial regression was applied to examine the association between long working hours and depressive symptoms after adjusting for potential confounders, including medical specialty and training year. All analyses were performed using STATA/SE version 13.0. Results: 86%(N=1,429) of interns and residents worked 60 hours or more per week. Compared to the "less than 60 hours" group, long working hours for interns and residents were significantly associated with depressive symptoms: "60-79 hours"(PR: 1.56, 95% CI: 1.05, 2.32), "80-99 hours"(PR: 2.27, 95% CI: 1.54, 3.33), "100-119 hours"(PR: 2.62, 95% CI: 1.76, 3.89), and "120-168 hours"(PR: 3.28, 95% CI: 2.21, 4.86). Conclusions: This study found that long working hours were prevalent among interns and residents in South Korea, and it was associated with depressive symptoms.

The Relationship between Home-Visit Nursing Services and Health Care Utilization among Nursing Service Recommended Beneficiaries of the Public Long-Term Care Insurance (노인장기요양보험 방문간호 권고군의 방문간호 이용과 의료 이용의 관계)

  • Kang, Sae Bom;Kim, Hongsoo
    • Health Policy and Management
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    • v.24 no.3
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    • pp.283-290
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    • 2014
  • Background: This study aimed to examine the relationship between home-visit nursing services and health care utilization under the public long-term care insurance program in Korea. Methods: We analyzed the long-term care need assessment database and the long-term care and the health insurance claim databases of National Health Insurance Service between July 2011 and June 2012. The sample includes a total of 20,065 home-visit nursing recommended-older beneficiaries who use home-visit nursing and/or home-visit care, based on a standard benefit model developed by the Health Insurance Policy Institute of National Health Insurance Service. The beneficiaries were categorized into home-visit nursing use and non-use groups, and the home-visit nursing use group was again divided into high-use and low-use groups home-visit nursing, based on their total annual home-visit nursing expenditure. Two-part models and negative-binomial regression models were used for the statistical analysis. Results: The home-visit nursing use was negatively associated with the number of outpatient visit and cost, while adjusting for all covariates. The home-visit nursing use was also negatively associated with the inpatient cost among the high home-visit nursing use group. Conclusion: The findings implies home-visit nursing use prevents health care utilization. Further studies and policy strategies that can promote and strengthen home-visit nursing services under the public long-term care insurance are necessary in Korea.

Estimation of the Expected Loss per Exposure of Export Insurance using GLM (일반화 선형모형을 이용한 수출보험의 지급비율 추정)

  • Ju, Hyo Chan;Lee, Hangsuck
    • The Korean Journal of Applied Statistics
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    • v.26 no.6
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    • pp.857-871
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    • 2013
  • Export credit insurance is a policy tool for export growth. In the era of free trade under the governance of WTO, export credit insurance is still allowed as one of the few instruments to increase exports. This paper, using data on short-term export insurance contracts issued to foreign subsidiaries of Korean companies, calculates the expected loss per exposure by combining the effect of risk factors (credit rate of foreign importers, size of mother company, and payment period) on loss frequency and loss severity in different levels. We, applying generalized linear models (GLM), first fit loss frequency and loss severity to negative binomial and lognormal distribution, respectively, and then estimate the loss frequency rate per contract and the ratio of loss severity to coverage amount. Finally, we calculate the expected loss per exposure for each level of risk factors by combining these two rates. Based on the result of statistical analysis, we present the implication for the current premium rate of export insurance.

An Empirical Study of Customer's Repeat Visit Frequency on the Internet (인터넷 이용자들의 웹사이트 재방문 빈도에 관한 실증적 연구)

  • Lee, Suke-Kyu
    • Journal of Global Scholars of Marketing Science
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    • v.11
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    • pp.129-146
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    • 2003
  • This study explores whether a NBD type of model can be applied to characterize the underlying frequency distribution of online consumer's visit behavior. In this study, the following two research questions are addressed: (1) How can we characterize the underlying distribution pattern(s) of the number of repeat i i visits to a site? (2) How can consumer's Internet usages and his/her demographics affect the average number of visits to the site? Through the empirical investigation, this study found that NBD models are directly applicable to characterize the underlying distribution of visit frequency on the Internet. Furthermore, this study addresses some managerial implications for understanding how site visits are determined. Especially this study highlights the relationship between repeated visits and the visitors' Internet Usages and demographics. The proposed models are estimated and validated by online panel data that covers more than 1000 different sites and has 800,000 observations.

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The Effects of Government Support and Regulation on SMEs Technology Innovation (정부지원과 규제장벽이 국내 중소기업의 기술혁신성과에 미치는 영향에 관한 연구)

  • Sohn, Dongseop;Lee, Jungsoo;Kim, Yunbae
    • Journal of Digital Convergence
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    • v.15 no.4
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    • pp.117-125
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    • 2017
  • The purpose of this study is to investigate the actual effect of government R&D support and regulation as a policy on technology innovation of SMEs. Because the previous studies did not consider the endogeneity of R&D support and made inconsistent conclusions in the case of regulation, the empirical research was conducted by logistic, negative binomial regression and 2SLS analysis for 1,223 SMEs. The analysis results show that government support has the effect for technology innovation even considering the endogeneity of government R&D support, and government regulation has a positive effect on technology innovation which supports Porter's theory. These results imply that government R&D support is important in inducing technology innovation because of the vulnerability of SMEs technology development environment and government should foster SMEs technology innovation through appropriate regulation policies rather than unconditional deregulation.