• Title/Summary/Keyword: resource intensity

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A simulation study on TCP performance for constrained IoT networks

  • Chansook, Lim
    • International Journal of Internet, Broadcasting and Communication
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    • v.15 no.1
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    • pp.1-7
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    • 2023
  • TCP is considered a major candidate transport protocol even for constrained IoT networks due to its ability to integrate into the existing network infrastructures. Since TCP implementations such as uIP TCP often allow only a single TCP segment per connection to be unacknowledged at any given time due to resource constraints, the congestion control relies only on RTO management. In our previous work, to address the problem that uIP TCP performs poorly particularly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe, we proposed a RTO scheme for uIP TCP and validated the performance through Cooja simulation. In this study, we investigate the effect of other factors that were not considered in our previous work. More specifically, the effect of traffic intensity, the degree of the hidden terminal problem, and RDC is investigated by varying the offered load and the transmission range, and the RDC channel check rate. Simulation results imply that we need to further investigate how to improve TCP performance when the radio duty cycling mechanism is used.

Effect of Transport Capacity Formula on Spatial Distribution of Soil Erosion

  • Nguyen, Van Linh;Yeon, Minho;Cho, Seongkeun;Lee, Giha
    • Proceedings of the Korea Water Resources Association Conference
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    • 2021.06a
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    • pp.150-150
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    • 2021
  • Soil erosion due to climate change is one of the global environmental issues. Especially, Korea is vulnerable to soil erosion as the frequency of extreme rainfall events and rainfall intensity are increasing. Soil erosion causes various problems such as reduced farmlands, deterioration of water quality in rivers, etc. To these severe problems, understanding the process of soil erosion is the first process. Then, it is necessary to quantify and analyze soil ersoion using an erosion model. Soil erosion models are divided into empirical, conceptual, and physics-based models according to the structures and characteristics of models. This study used GSSHA (Gridded Surface Subsurface Hydrologic Analysis), the physics-based erosion model, running on WMS (Watershed Modeling System) to analyze soil erosion vulnerability of the CheonCheon watershed. In addition, we compared the six sediment transport capacity formulas provided in the model and evaluated the equations fir on this study site. Therefore, this result can be as a primary tool for soil conservation management.

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Data resource profile: the Korean Working Conditions Survey (KWCS)

  • Yoonho Cho
    • Annals of Occupational and Environmental Medicine
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    • v.35
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    • pp.49.1-49.7
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    • 2023
  • The Korean Working Conditions Survey (KWCS) is a state-approved statistical survey that has been conducted by the Occupational Safety and Health Research Institute (OSHRI) every 3 years since 2006 to monitor changes in the working conditions of Koreans. This cross-sectional national survey involves a sample of 50,000 employed people aged 15 or older. KWCS measures various working conditions through > 130 survey questions, including questions regarding working hours, labor intensity, work-life balance, degree of exposure to risk factors, and subjective health status. Professional survey interviewers visit households and conduct face to face interviews. KWCS provides data and statistics for occupational safety and health polices and research in Korea. Furthermore, OSHRI holds academic conferences every year, awards high-quality academic papers, and supports researchers using data. Microdata is publicly available through the OSHRI website (https://oshri.kosha.or.kr).

Antecedents of Manufacturer's Private Label Program Engagement : A Focus on Strategic Market Management Perspective (제조업체 Private Labels 도입의 선행요인 : 전략적 시장관리 관점을 중심으로)

  • Lim, Chae-Un;Yi, Ho-Taek
    • Journal of Distribution Research
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    • v.17 no.1
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    • pp.65-86
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    • 2012
  • The $20^{th}$ century was the era of manufacturer brands which built higher brand equity for consumers. Consumers moved from generic products of inconsistent quality produced by local factories in the $19^{th}$ century to branded products from global manufacturers and manufacturer brands reached consumers through distributors and retailers. Retailers were relatively small compared to their largest suppliers. However, sometime in the 1970s, things began to slowly change as retailers started to develop their own national chains and began international expansion, and consolidation of the retail industry from mom-and-pop stores to global players was well under way (Kumar and Steenkamp 2007, p.2) In South Korea, since the middle of the 1990s, the bulking up of retailers that started then has changed the balance of power between manufacturers and retailers. Retailer private labels, generally referred to as own labels, store brands, distributors own private-label, home brand or own label brand have also been performing strongly in every single local market (Bushman 1993; De Wulf et al. 2005). Private labels now account for one out of every five items sold every day in U.S. supermarkets, drug chains, and mass merchandisers (Kumar and Steenkamp 2007), and the market share in Western Europe is even larger (Euromonitor 2007). In the UK, grocery market share of private labels grew from 39% of sales in 2008 to 41% in 2010 (Marian 2010). Planet Retail (2007, p.1) recently concluded that "[PLs] are set for accelerated growth, with the majority of the world's leading grocers increasing their own label penetration." Private labels have gained wide attention both in the academic literature and popular business press and there is a glowing academic research to the perspective of manufacturers and retailers. Empirical research on private labels has mainly studies the factors explaining private labels market shares across product categories and/or retail chains (Dahr and Hoch 1997; Hoch and Banerji, 1993), factors influencing the private labels proneness of consumers (Baltas and Doyle 1998; Burton et al. 1998; Richardson et al. 1996) and factors how to react brand manufacturers towards PLs (Dunne and Narasimhan 1999; Hoch 1996; Quelch and Harding 1996; Verhoef et al. 2000). Nevertheless, empirical research on factors influencing the production in terms of a manufacturer-retailer is rather anecdotal than theory-based. The objective of this paper is to bridge the gap in these two types of research and explore the factors which influence on manufacturer's private label production based on two competing theories: S-C-P (Structure - Conduct - Performance) paradigm and resource-based theory. In order to do so, the authors used in-depth interview with marketing managers, reviewed retail press and research and presents the conceptual framework that integrates the major determinants of private labels production. From a manufacturer's perspective, supplying private labels often starts on a strategic basis. When a manufacturer engages in private labels, the manufacturer does not have to spend on advertising, retailer promotions or maintain a dedicated sales force. Moreover, if a manufacturer has weak marketing capabilities, the manufacturer can make use of retailer's marketing capability to produce private labels and lessen its marketing cost and increases its profit margin. Figure 1. is the theoretical framework based on a strategic market management perspective, integrated concept of both S-C-P paradigm and resource-based theory. The model includes one mediate variable, marketing capabilities, and the other moderate variable, competitive intensity. Manufacturer's national brand reputation, firm's marketing investment, and product portfolio, which are hypothesized to positively affected manufacturer's marketing capabilities. Then, marketing capabilities has negatively effected on private label production. Moderating effects of competitive intensity are hypothesized on the relationship between marketing capabilities and private label production. To verify the proposed research model and hypotheses, data were collected from 192 manufacturers (212 responses) who are producing private labels in South Korea. Cronbach's alpha test, explanatory / comfirmatory factor analysis, and correlation analysis were employed to validate hypotheses. The following results were drawing using structural equation modeling and all hypotheses are supported. Findings indicate that manufacturer's private label production is strongly related to its marketing capabilities. Consumer marketing capabilities, in turn, is directly connected with the 3 strategic factors (e.g., marketing investment, manufacturer's national brand reputation, and product portfolio). It is moderated by competitive intensity between marketing capabilities and private label production. In conclusion, this research may be the first study to investigate the reasons manufacturers engage in private labels based on two competing theoretic views, S-C-P paradigm and resource-based theory. The private label phenomenon has received growing attention by marketing scholars. In many industries, private labels represent formidable competition to manufacturer brands and manufacturers have a dilemma with selling to as well as competing with their retailers. The current study suggests key factors when manufacturers consider engaging in private label production.

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Properties of Solar Radiation Components Reflected by the Sea Surface: - A Case of Jeju Island, South Korea - (해수면에 의해 반사된 태양복사 성분의 특성: 남한의 제주도 사례)

  • Fumichika, Uno;Hayashi, Yousay;Hwang, Soo-Jin;Kim, Hae-Dong
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.13 no.2
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    • pp.48-55
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    • 2011
  • Solar radiation components reflected by the sea surface ($R_{ss}\uparrow$) are additional energy sources comprising the solar radiation regime. Previous studies, based on observational approaches, indicated that $R_{ss}\uparrow$ is an available climatological resource. However, an estimation process for $R_{ss}\uparrow$ has not been established. In this case study over Jeju Island in South Korea, we applied a new estimation process to solar radiation modeling and discussed the spatial distribution of $R_{ss}\uparrow$ and its seasonal variation. Our results showed that the illuminated area and the intensity of $R_{ss}\uparrow$ became greatest at the winter solstice and least at the summer solstice. We estimated the illuminated area of $R_{ss}\uparrow$ as it expanded over the southern slope of Jeju Island. At the winter solstice, on a daily basis, the area and intensity of illumination by $R_{ss}\uparrow$ were $182.3km^2$ and $0.41\;MJ\;m^{-2}\;day\;{-1}$, respectively. Comparing the daily accumulative and instantaneous values of $R_{ss}\uparrow$ intensity, the difference was about 20 times greater in daily cases than in instantaneous cases. On the other hand, for instantaneous values, the $R_{ss}\uparrow$ intensity accounted for up to 33% of the three components, i.e., direct, diffuse and reflected radiation in winter solstice. In addition, it was estimated that the sea surface reflectance depended on the wind speed. Therefore, in a practical use of this revised model, wind conditions should be considered as a critical factor in estimating $R_{ss}\uparrow$.

Estimation of willingness to pay of workers who are engaged in nuclear power R&D projects to avoid exposure to radioactive matters by using a choice experiment (선택실험설문에 의한 방사능 피폭 가능성에 대한 원자력 기술개발 종사자의 지불용의액 추정)

  • Bae, Jeong Hwan
    • Environmental and Resource Economics Review
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    • v.22 no.3
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    • pp.411-435
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    • 2013
  • Since catastrophe from explosion of Hukushima nuclear power plant, concerns over possibility of exposure to radioactive matter has been disseminating all over the world and frequent accidents of domestic nuclear power plants also has been amplifying throughout the nation. In the past, major focus was made on compensation for local residents who live nearby nuclear power plants, but focal point of this study is on wage premium of workers who are employed in R&D of nuclear power plants. It is difficult to derive socially desirable result if private sectors are responsible for compensation on workers who suffer from physical damages due to the exposure to radioactive matter. Because victims should verify the damages that occur in the working places. This study conducted a survey on which job would prefer the respondents who are engaged with the nuclear R&D projects as exposure levels to radioactive matter, security of job, location of firms, and work intensity differ. As a result, exposure to radioactive matter was the most important attribute in choosing alternative jobs followed by job security, work intensity and job location. Annual willingness to pay for reduction of exposure to radioactive matter was estimated as 7730~7770 thousand KRW depending on different econometric models. Therefore, Korean government should prepare institutional foundation in order that appropriate compensation should be made on workers who are engaged in R&D projects on nuclear power plants if they have damages from the exposure to radioactive matter.

A Comparison of Decomposition Analyses for Primary and Final Energy Consumption of Korea (우리나라 1차 에너지와 최종 에너지 소비 변화요인 분해 비교분석)

  • Park, Sungjun;Kim, Jinsoo
    • Environmental and Resource Economics Review
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    • v.23 no.2
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    • pp.305-330
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    • 2014
  • There has been a lot of studies to identify the driving forces of energy consumption. Many of them decomposed the final energy consumption into the intensity effect, structural effect, and production effect. Those approach, however, could not consider the transformation loss during the electric power generation. Therefore, in this study, we conducted a decomposition analysis on the primary energy use basis to reflect that transformation loss. Log mean Divisia index and refined Laspeyres methods were used for the index decomposition. As results, we could find out that the difference between two approaches were definite. The intensity effect in 2011 is -0.607 times against 1981 in the final energy case, but -0.236 times in the primary energy case. The structure effect in 2011 is 0.227 times against 1981 in the final energy case, but 0.434 times in the primary energy case. Therefore, an analysis on the primary energy basis is essential when conducting a decomposition analysis.

A Study on the Characteristics of Local Energy Consumption by Using Index Decomposition Analysis (지수분해분석을 이용한 지자체의 에너지 소비특성에 관한 연구)

  • Jin, Sang Hyeon;Hwang, In Chang
    • Environmental and Resource Economics Review
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    • v.18 no.4
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    • pp.557-586
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    • 2009
  • Although energy demand management policy attracts attention internationally and domestically, the importance of local government in this policy is not so much as central government. But local government can do a role with regard to this policy because it is close to energy consumers not like central government. So local energy plan should be based on the understanding local energy consumption characteristics to activate local energy demand management policy. This paper tries to analyze energy characteristics of 16 local governments by decomposing energy consumption into population, production and intensity factors. The result of index decomposition analysis shows that energy intensity improvement has offset the increase of energy consumption caused by economic growth in the metropolitan cities, while it couldn't offset in the other provinces because of industrialization based on the manufacturing. In conclusion, this paper suggests that it will be necessary to switch to low energy society by carrying out concrete energy efficiency improvement projects in the metropolitan cities while it will be helpful to make a local development plan for low energy intensive industrialization in the other provinces.

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Estimation of Moisture Content in Comminuted Miscanthus based on the Intensity of Reflected Light

  • Cho, Yongjin;Lee, Dong Hoon
    • Journal of Biosystems Engineering
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    • v.40 no.3
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    • pp.296-304
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    • 2015
  • Purpose: The balance between miscanthus production and its cost effectiveness depends greatly on its moisture content during post processing. The objective of this research was to measure the moisture content using a non-destructive and non-contact methodology for in situ applications. Methods: The moisture content of comminuted miscanthus was controlled using a closed chamber, a humidifier, a precision weigher, and a real-time monitoring software developed in this research. A CMOS sensor equipped with $50{\times}$ magnifier lens was used to capture magnified images of the conditioned materials with moisture content level from 5 to 30%. The hypothesis is that when light is incident on the comminuted particles in an inclined manner, higher moisture content results in light being reflected with a higher intensity. Results: A linear regression analysis for an initiative hypothesis based on general histogram analysis yielded insufficient correlations with low significance level (<0.31) for the determination coefficient. A significant relationship (94% confidence level) was determined at level 108 in a reverse accumulative histogram proposed based on a revised hypothesis. A linear regression model with the value at level 108 in the reverse accumulative histogram for a magnified image as the independent variable and the moisture content of comminuted miscanthus as the dependent variable was proposed as the estimation model. The calibrated linear regression model with a slope of 92.054 and an offset of 32.752 yielded 0.94 for the determination coefficient (RMSE = 0.2%). The validation test showed a significant relationship at the 74% confidence level with RMSE 6.4% (n = 36). Conclusions: To compensate the inconsistent significance between calibration and validation, an estimation model robust against various systematic interferences is necessary. The economic efficiency of miscanthus, which is a promising energy resource, can be improved by the real-time measurement of its crucial material properties.

Effects of External Environment and Organizational Resources and Capabilities on Strategy and Performance: An evidence from an analysis on ventures (벤처기업의 전략 및 성과에 대한 외부환경과 조직자원 및 능력의 영향)

  • Song, Woo-Yong;Hwang, Kyung-Yun
    • The Journal of the Korea Contents Association
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    • v.12 no.2
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    • pp.369-387
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    • 2012
  • Based on the survey data, this study focused venture firms examines how organizational resources and capabilities along with its external environmental conditions have an effect on its strategy and performance. In particular, this article attempts, by performing a binary logistic regression analysis, to identify the venture-specific importance and priority of the factors that may influence firms' strategy patterns, with multiple regression analysis on the relationships between some variables included in the model. The survey was conducted from October 1, 2010 through October 30, 2010. The results of this study are the following. First, the more firms are exposed to high industry growth and low competitive intensity, the higher chance they get to pursuit aggressive strategy. And then a firm seeks aggressive strategy, when it has more technological resources and human resources. Third, environmental uncertainty, industry growth, technological resources, human resources, financial resources and marketing capabilities have positive effects on firm's performance. But, competitive intensity has no direct influence firm's performance. Finally, CEO competence directly influences firm's performance, but the interaction. of CEO competence with other variables is not significant.