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Study of Virtual Goods Purchase Model Applying Dynamic Social Network Structure Variables (동적 소셜네트워크 구조 변수를 적용한 가상 재화 구매 모형 연구)

  • Lee, Hee-Tae;Bae, Jungho
    • Journal of Distribution Science
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    • v.17 no.3
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    • pp.85-95
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    • 2019
  • Purpose - The existing marketing studies using Social Network Analysis have assumed that network structure variables are time-invariant. However, a node's network position can fluctuate considerably over time and the node's network structure can be changed dynamically. Hence, if such a dynamic structural network characteristics are not specified for virtual goods purchase model, estimated parameters can be biased. In this paper, by comparing a time-invariant network structure specification model(base model) and time-varying network specification model(proposed model), the authors intend to prove whether the proposed model is superior to the base model. In addition, the authors also intend to investigate whether coefficients of network structure variables are random over time. Research design, data, and methodology - The data of this study are obtained from a Korean social network provider. The authors construct a monthly panel data by calculating the raw data. To fit the panel data, the authors derive random effects panel tobit model and multi-level mixed effects model. Results - First, the proposed model is better than that of the base model in terms of performance. Second, except for constraint, multi-level mixed effects models with random coefficient of every network structure variable(in-degree, out-degree, in-closeness centrality, out-closeness centrality, clustering coefficient) perform better than not random coefficient specification model. Conclusion - The size and importance of virtual goods market has been dramatically increasing. Notwithstanding such a strategic importance of virtual goods, there is little research on social influential factors which impact the intention of virtual good purchase. Even studies which investigated social influence factors have assumed that social network structure variables are time-invariant. However, the authors show that network structure variables are time-variant and coefficients of network structure variables are random over time. Thus, virtual goods purchase model with dynamic network structure variables performs better than that with static network structure model. Hence, if marketing practitioners intend to use social influences to sell virtual goods in social media, they had better consider time-varying social influences of network members. In addition, this study can be also differentiated from other related researches using survey data in that this study deals with actual field data.

Product Market Competition and Corporate Social Responsibility Activities (제품 시장 경쟁 및 기업의 사회적 책임 활동)

  • RYU, Hae-Young;CHAE, Soo-Joon
    • The Journal of Industrial Distribution & Business
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    • v.10 no.11
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    • pp.49-56
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    • 2019
  • Purpose: Corporate social responsibility is a self-regulating business model that helps a firm be socially accountable to the public. By practicing corporate social responsibility, firms can be conscious of the kind of impact they are having on all aspects of society, including economic, social, and environmental. Corporate social responsibility activities are not directly linked to increasing corporate performance and corporate value, but rather involve spending expenses. Based on these facts, this study verifies whether the effects of corporate social responsibility activities differ depending on the firm's situation. Research design, data and methodology: This study analyzed the effect of market competition on corporate social responsibility activities using logistic regression analysis on listed companies in the KOSPI and KOSDAQ for fiscal years 2014 through 2016. In this study, market competition was measured using the Herfindahl-Herschman Index(HHI). Higher HHI value can be interpreted as a lower degree of market competition. We also measured corporate social responsibility activities using the KEJI Index published by the Korea Economic Justice Institute (KEJI). If a firm-year is included in the top 200 companies of the KEJI Index, it is classified as a good corporate social responsibility activity firm. Results: We find that companies in less competitive market were not included in the KEJI Index. This result indicates that firms in the market with lower market competition perform less corporate social responsibility activities that incur costs. An additional analysis showed that there was a significant negative relationship between the market competition and the corporate social responsibility activity scores published by the KEJI Index. These result adds robustness to the result of the hypothesis that firms that have a monopolistic place in the market practice passive corporate social responsibility activities. Conclusions: The results show that managers of a firm in the lower market competition have a lower incentive to use limited resources for projects that are not directly related to revenue. The results of this study imply that corporate social responsibility activities vary according to the position of the business. Therefore, this study suggests that market investors should consider the degree of competition in the market when they evaluate corporate social responsibility activities.

Syntaxonomical and Synecological Description on the Forest Vegetation of Juwangsan National Park, South Korea (주왕산국립공원 삼림식생의 군락분류와 군락생태)

  • Oh, Hae-Sung;Lee, Gyeong-Yeon;Kim, Jong-Won
    • Korean Journal of Environment and Ecology
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    • v.32 no.1
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    • pp.118-131
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    • 2018
  • The forest vegetation of Juwangsan National Park, which is famous for its towering scenic valleys, was syntaxonomically described. The study adopted the $Z{\ddot{u}}rich$-Montpellier School's method emphasizing a matching between species composition and habitat conditions. A combined cover degree and the r-NCD (relative net contribution degree) were used to determine a performance of 265 plant species listed-up in a total of 52 phytosociological $relev{\acute{e}}s$. Nine plant communities were classified through a series of table manipulations, and their distribution and actual homotoneity($H_{act}$) were analyzed. Syntaxa described were Carex gifuensis-Quercus mongolica community, Athyrium yokoscense-Quercus mongolica communiy, Arisaema amurense-Quercus serrata community, Lespedeza maximowiczii var. tomentella-Quercus variabilis community, Tilia rufa-Quercus dentata community, Carex ciliatomarginata-Carpinus laxiflora community, Aristolochia manshuriensis-Zelkova serrata community, Onoclea orientalis-Fraxinus mandshurica community, and Carex humilis var. nana-Pinus densiflora community. A zonal distribution was reviewed and the altitude of about 700 m was the transition zone between the cool-temperate central montane zone (Lindero-Quercenion mongolicae region) and southern submontane zone (Callicarpo-Quercenion serratae region). Only 19 taxa were associated with r-NCD 10% or more, most of which were tree species occurring in the Lindero-Quercenion and some of which was a member of open forests. Species composition of forest vegetation was much less homogeneous, showing the lowest $H_{act}$. Nearly natural forests and/or secondary forests in the Juwangsan National Park were defined as a regional vegetation type, which reflects much stronger continental climate in the Daegu regional bioclimatic subdistrict, rhyolitic tuff predominant, and wildfire interference.

Quality Characteristics of Wheat Flours from New Released Iksan370 with Long Spike and Domestic Wheat Cultivars (신육성 다수확 밀 익산370호의 원맥과 밀가루의 품질 특성)

  • Choi, Yong-Seok;Lee, Jae-Kang;Choi, Yong-Hyun;Kim, Young-Hwan;Kang, Chon-Sik;Shin, Malsik
    • Korean journal of food and cookery science
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    • v.31 no.5
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    • pp.551-556
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    • 2015
  • Iksan370 is a long-spike wheat developed by the Rural Development Administration yielding excellent features components such as cold resistance, disease resistance, and viviparous germination. The physicochemical and material properties of the raw wheat and milled flour of Iksan370 were analyzed to derive its appropriate uses. The raw wheat of Iksan370 showed high contents of ash and proteins at 1.71% and 13.7%, respectively. Its test weight of 763.0 g/L was similar to those of other varieties and its 1,000 kernel weight was high at 45.38 g. The milled flour of Iksan370 had an ash content of 0.45%, which corresponds with a class 1 flour, and its protein content is 12.18%, corresponding with strong flour. The damaged starch was 5.41%, which was lower than that of other varieties. The average grain size was $70.67{\mu}m$ and the grain distribution was at the level of a typical hard wheat. In the farinogram, the water absorption was 58.63%, which corresponded to the level of medium flour. The development time was 7.00 minutes, which was significantly lower than those of Jokyung and Keumkang. The degree of softening was 67.00 BU, similar to those of Yunbaek and Baekjoong. Among the physico-chemical characteristics, the high protein content and typical hard wheat grain distribution of Iksan370 were similar to those of strong wheat, usually used for bread making. However, in the farinogram, the dough development time was short and the degree of softening was high. As a result, Iksan370 was expected to have poor breadmaking properties and a small volume of the final bread product due to insufficient dough durability. On the other hand, Iksan370 showed the highest maximum gelatinization viscosity at 864.00 BU. Therefore, Iksan370 is expected to show glutinous texture when used for noodles and its flour appears to be appropriate for frying powders as well.

Anodic Properties of Needle Cokes-derived Graphitic Materials in Lithium Secondary Batteries (침상 코크스(needle cokes)로부터 제조된 흑연질 탄소재료의 리튬 2차전지 음극특성)

  • Park Chul Wan;Oh Seung M.
    • Journal of the Korean Electrochemical Society
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    • v.2 no.4
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    • pp.221-226
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    • 1999
  • Two needle cokes (NC-A and NC-B) that differ in both the texture and impurity content to each other were graphitized at $2000-3000{\circ}C$, and the average particle size, size distribution and surface area were compared after milling. Their anodic properties in Li secondary batteries were also analyzed. Two materials showed a higher degree of graphitization with an increase in the preparation temperature, however, the NC-B series was less graphitized than NC-A due to the presence of impurities and less ordered mosaic texture. The mein particle size of the milled powder was proportional to the degree of graphitization, but the surface area showed the opposite trend. The highly graphitized materials yielded powders of lower uniformity in the size distribution. The discharge capacity of the resulting carbons steadily decreased in the temperature range of 1000 to $2000^{\circ}C$ due to the depletion of carbonaceous interlayers that contain crystal defects. A later increase in the discharge capacity was observed at $>2000^{\circ}C$, which arises from the formation of graphitic interlayers. The milling process gave rise to a sloping discharge curve at >1.0 V, but this was converted to a plateau at <0.25V after a repeated cycling or additional heat-treatment at $1000^{\circ}C$. The discharge at >1.0V likely comes from the disordered surface structure formed during the milling process. The evolution of a plateau at <0.25 V suggests that this disordered structure transforms to a more ordered graphitic one upon a cell cycling or heat-treatment.

A Study on the Distribution Status of Nationalized Plants in Traditional Cultural Spaces in Seoul - Focused on 4 Ancient Palaces and Jongmyo Shrine - (서울시 전통문화공간의 귀화식물 분포현황 - 4대 고궁과 종묘를 중심으로 -)

  • Kang, Min-Jung;Lee, Go-Woon;Kim, Shin-Won
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.36 no.1
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    • pp.45-54
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    • 2018
  • This study aims to study the flora and identify the naturalized plants of the 4 ancient palace (Gyeongbokgung, Changdeokgung, Changgyeonggung, Deoksugung) and Jongmyo Shrine, which are national cultural heritage and urban cultural centers in Seoul. The plants found consisted of 315 taxa in total, belonging to 82 families, 201 genera, 285 species, 1 subspecies and 29 varieties. The naturalized plants were shown as follows: in the Deoksugung Palace(33 taxa), the Jongmyo Shrine(14 taxa) and the Gyeongbok Palace(21 taxa) and the Changdeokgung Palace complex(11 taxa). The results of the analysis based on the place of origin showed a higher rate of distribution of species based in North America, Europe and Eurasia, with higher rates of grass than tree. In addition, except for Gyeongbokgung Palace, the annual rate is higher than the perennial rate. As a result of naturalization analysis, the percentage of naturalized plants corresponding to naturalization degree 3 and naturalization degree 5 was high. According to the moment of the invasion, the naturalized plants recently introduced were higher than the first species. In addition, it was found that the similarity between the sites was more than 40%, and the diversity of species of naturalized plants common to the five sites was very low. The purpose of this study is to provide basic data for cultural heritage landscaping and naturalized plant management.

Review of Compositional Evaluation Items for Environmental Conservation Value Assessment Map(ECVAM) of National Land in Korea (국토환경성평가지도 평가항목 구성의 적정성 검토)

  • Jeon, Seong Woo;Lee, Moung Jin;Song, Won Kyong;Sung, Hyun Chan;Park, Wook
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.11 no.1
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    • pp.1-13
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    • 2008
  • This study review of Compositional Evaluation Items for Environmental Conservation Value Assessment Map (ECVAM) in Korea. The ECVAM is composed of legal assessment and environmental/ecological assessment items. ECVAM basically adapts an overlay method for environmental/ecological assessment items. The objective of this study is to suggest supplementary items for the ECVAM with the following process : Overlapping rates of the assessment items in the ECVAM are calculated to understand the grade distribution of the environmental conservation value assessment and to analyze the overlapping rates among the assessment items, as a result it is found that various items are overlapped each other. In order to reflect effectively each assessment item to the ECVAM, Analyzed the overlapping degree among assessment items to be applied to this map. On the concrete we gripped results to be assessed by various items, which were overlapped each other. In order to reflect effectively each assessment item to the environmental conservation value assessment map of national land, we analyzed the overlapping degree on environmental/ecological items, and investigated the grade distribution by field survey. In this study we assessed the ECVAM by 5 kinds of method. Method 1 is Grade 1 areas of each administrative district, Method 2 is Comparing overlapping areas of each assessment items Grade 1, 2 and Permission of each assessment items' duplication, Method 3 is Grade 1, 2 areas by only singular assessment items, Method 4 is Only Grade 1 areas of Method 2 and Method 5 is Only Grade 2 areas of Method 2. As results, Method 1 showed Seoul and other metropolitan cities reveal a high proportion of Grade I regions by the legal assessment items. Kangwon-Do, show a high proportion of Grade I regions by the environmental/ecological assessment item. Method 2 showed 93.4% of diameter Grade II(standard for stability), forest diameter item was accounted for 99.9% by Method 3, Method 4 showed 95.7% of forest diameter and forest density was accounted for 66.4% by Method 5. From now on, this study will contribute to reduce the complexity in the process of manufacturing ECVAM of National Land, and to raise the pliability in the process of managing and updating this map.

Quality Characteristics of Retorted Chicken Breast Products Packaged in a Multilayer Barrier Tray During Chilled Storage (차단성 다층 트레이에 포장된 레토르트 닭 가슴살제품의 냉장 중 품질 특성)

  • Jang, Dong-Hyun;Lee, Keun-Taik
    • Food Science of Animal Resources
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    • v.32 no.4
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    • pp.483-490
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    • 2012
  • Ready-to-eat chicken breasts were packaged in a multilayer, gas-tight tray with top film and various quality changes were investigated during the 24 wk of storage at $10^{\circ}C$. Over the storage period, total aerobes, mesophilic aerobic and anaerobic spore formers, and Clostridium spp. were not detected above 1.0 log CFU/g (detection limit). The residual oxygen ratio in the head space of tray and pH values tended to decrease with storage time, namely from initial values of 5.7% and 6.56 to 3.3% and 6.34 at week 24, respectively. Thiobarbituric acid reactive substances and volatile basic nitrogen values increased from 0.52 mg malonaldehyde (MA)/kg and 2.1 mg/100 g initially, to 3.70 mg MA/kg and 39.9 mg/100 g at week 24, respectively. In terms of the change in meat color during storage, the samples showed a slight increasing trend of CIE $a^*$, $b^*$, and ${\Delta}E$ values over the storage period until week 24 (p<0.05). The change in brine color showed a similar trend with meat of which Hunter $b^*$ and ${\Delta}E$ values increased slightly during storage during 24 wk (p<0.05). The values for the transmittance degree of brine in the samples tended to decrease. Moreover, values for the absorbance degree tended to increase with storage time until week 24. The sensory scores for color, texture, odour, and flavour were evaluated below 5.0 (marketability level) after 24 wk of storage. Based on this sensory evaluation, it could be concluded that retorted RTE chicken breast could remain marketable for at least 20 wk at $10^{\circ}C$.

Evaluation of Fine Dust Diffusion and Contamination Degree : Focused on the Operation Status of Donghae Port (항만 인근 미세먼지 노출 영향권 및 오염도 분석 :동해항 운영현황을 중심으로)

  • Hwang, Je-Ho;Kim, Si-Hyun;Kang, Dal-Won
    • Journal of Navigation and Port Research
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    • v.46 no.3
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    • pp.251-258
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    • 2022
  • Donghae Port is adjacently located to a residential area wherein 26,933 generations are creating a living environment. The areas comprise Song-jeong village (5,754 generations) and Bukp-yeong village (21,179 generations). Major cargoes handled in Donghae Port are dusty limestone, cement, anthracite, and bituminous coal, etc. In the process of handling such cargoes, air pollutants including oxide dust and fine dust which adversely impact the living conditions and health of residents are generated, causing air pollution in the vicinity of the port. Currently, Donghae Port is making an effort to improve the operation environment of the infrastructure and equipment in stages, for the purpose of reducing air pollutant emissions caused by the port industries in a long-term perspective. In this study, the sphere of influence of fine dust exposure and the degree of air pollution in the surrounding area were analyzed such as the state of fine dust concentration and diffusion in the vicinity of Donghae Port, fine dust diffusion pattern and spatial distribution of high-concentration considering wind direction and speed characteristics during the day and seasonal cycles. A more effective plan to reduce the concentration of fine dust in nearby areas by combining reduction plan, is being developed in terms of improvement regarding port infrastructure and equipment, and reduction measures considering the characteristics of the atmosphere environment according to the daytime, nighttime and season.

A photoelastic study on the initial stress distribution of the upper anterior teeth retraction using combination loop archwire and sliding mechanics (Combination loon archwire와 활주역학을 이용한 상악전치의 후방 견인시 나타나는 초기 응력 분포에 관한 광탄성학적 연구)

  • Yim, Kang-Soon;Lee, Jin-Woo;Cha, Kyung-Suk
    • The korean journal of orthodontics
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    • v.34 no.4 s.105
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    • pp.303-312
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    • 2004
  • An unfavorable tipping movement can occur during the retraction of anterior teeth because orthodontic force is loaded by brackets positioned far from the center of resistance. To avoid this unfavorable movement, a compensating curved wire or lingual root torque wire is used. The purpose of this study is to investigate, using photoelastic material, the distribution of initial stress associated with the retraction of the incisors according to the degree of the compensating curve, to model changes associated with tooth ud alveolar bone structure. The following results were obtained by analysis of the polarizing plate of the effects of initial stress resulting from retraction of the anterior teeth: 1. When the incisors were retracted using combination archwire or sliding mechanics, the maximal polarizing pattern of the apical area decreased as the degree of the compensating owe increased from 0 to 15 to 30. 2. When the incisors were retracted by the combination archwire or sliding mechanics, the maximal polarizing pattern of the canine and premolar area increased as the degree of the compensating curve increased from 0to 15to 30. 3. A lower degree of polarizing patterns were associated with the combination archwire technique than the sliding mechanics technique at a given force. The above results indicate that there is no significant difference between the combination loop archwire technique and sliding mechanics, for the retraction of maxillary anterior teeth with decreased lingual tipping tendency by a compensating curve on the arch wire. However, the use of sliding mechanics is more effective for the prevention of lingual inclination of the anterior teeth, because the hook used in sliding mechanics is closer to the center of resistance of the maxillary anterior teeth.