• Title/Summary/Keyword: Model Reduction

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Feasibility of Tax Increase in Korean Welfare State via Estimation of Optimal Tax burden Ratio (적정조세부담률 추정을 통한 한국 복지국가 증세가능성에 관한 연구)

  • Kim, SeongWook
    • 한국사회정책
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    • v.20 no.3
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    • pp.77-115
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    • 2013
  • The purpose of this study is to present empirical evidence for discussion of financing social welfare via estimating optimal tax burden in the main member countries of the OECD by using Hausman-Taylor method considering endogeneity of explanatory variables. Also, the author produced an international tax comparison index reflecting theoretical hypotheses on revenue-expenditure nexus within a model to compare real tax burden by countries and to examine feasibility of tax increase in Korea. As a result of the analysis, the higher the level of tax burden was, the higher the level of welfare expenditure was, indicating the connection between high burden and high welfare from the aspect of scale. The results also indicated that the subject countries recently entered into the state of low tax burden. Meanwhile, Korea had maintained low burden until the late 1990s but the tax burden soared up since the financial crisis related to the IMF. However, due to the impact of foreign economy and the tax reduction policy, it reentered into the low-burden state after 2009. On the other hand, the degree of social welfare expenditure's reducing tax burden has been gradually enhanced since the crisis. In this context, the current optimal tax burden ratio of Korea as of 2010 may be 25.8%~26.5% of GDP based on input of welfare expenditure variables, a percent that Korea was investigated to be a 'high tax burden-low ITC' country whose tax increase of 0.7~1.4%p may be feasible and that the success of tax system reform for tax increase might be higher probability when compare to others. However, measures of increasing social security contributions and consumption tax were analyzed to be improper from the aspect of managing finance when compared to increase in other tax items, considering the relatively higher ITC. Tax increase is not necessarily required though there may be room for tax increase; the optimal tax burden ratio can be understood as the level that may be achieved on average when compared to other nations, not as the "proper" level. Thus, discussion of tax increase should be accompanied with comprehensive understanding of models of economic developmental difference from nations and institutional & historical attributes included in specific tax mix.

Anti-obesogenic Effect of Brassica juncea Extract on Bisphenol-A Induced Adipogenesis of 3T3-L1 Cells (비스페놀 A (Bisphenol-A)로 유도된 지방세포 분화에 미치는 갓 추출물의 항오비소겐 효과)

  • Lee, Se-jeong;Na, Uoon-Joo;Choi, Sun-Il;Han, Xionggao;Men, Xiao;Lee, Youn Hwan;Kim, Hyun Duk;Kim, Yoon Jung;Lee, Ok-Hwan
    • Journal of Food Hygiene and Safety
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    • v.36 no.6
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    • pp.528-536
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    • 2021
  • The purpose of the study was to investigate the content of sinigrin, an index component, in Brassica juncea extract and to evaluate the differentiation of lipocytes, inhibition of production of reactive oxygen species (ROS) and reduction of protein production by lipogenic factors (PPARγ, C/EBPα, aP2) in the processing of Brassica juncea extract and sinigrin in 3T3-L1 preadipocytes which induces Bisphenol A (BPA), an endocrine disrupting environmental hormone. From the investigation, the content of sinigrin in Brassica juncea extract, measured by HPLC, is found to be 21.27±0.2 mg/g. The XTT assay result on BPA-derived 3T3-L1 adipocytes shows there is no cytotoxicity found from 180 µM of sinigrin and 300 ㎍/mL of Brassica juncea extract. Moreover, both intracellular lipid accumulation and ROS production during differentiation of lipocyte are significantly reduced in cells processed with Brassica juncea extract and sinigrin. Lastly, it was also found that the production of transcription factors of lipocyte differentiation, PPARγ, C/EBPα and aP2, were found to be suppressed by the application of Brassica juncea extract and sinigrin. Such results reveals that Brassica juncea is effective in not only suppressing lipid accumulation in the environmental hormone bisphenol A-derived lipocyte, but also in reducing the ROS. The sinigrin-containing Brassica juncea is highly expected to be used in natural functional supplements that prevents the lipid metabolism disorders caused by BPA. There are necessities for additional clinical research and follow-up studies on the in vivo model to verify the relevant mechanisms.

Analysis of Economic and Environmental Effects of Remanufactured Furniture Through Case Studies (사례분석을 통한 사용 후 가구 재제조의 경제적·환경적 효과 분석)

  • Lee, Jong-Hyo;Kang, Hong-Yoon;Hwang, Yong Woo;Hwang, Hyeon-Jeong
    • Resources Recycling
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    • v.31 no.5
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    • pp.67-76
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    • 2022
  • The furniture industry has a high possibility to create value-added and a high potential to create new occupations due to the characteristics of the industry, which mainly consists of small and medium-sized enterprises (SMEs). However, the used furniture, which has sufficient reuse value, is also crushed and used as solid refuse fuel (SRF) recently. Besides, the number of waste treatment companies continues to decrease, and it occurs congestion of wood waste. As a way to solve the issue, a business model development of remanufacturing used furniture can be suggested as an alternative due to its high circular economic efficiency. Remanufacturing business including furniture industry creates positive effects in various aspects such as economic, environmental and job creation. In other words, remanufacturing is an effective recycling way to reduce input resources and energy in the production process. The results of economic analysis show that the expected annual revenue from the single worker furniture remanufacturing site was 104 million won which is 3.11 times more than the average income of a single-worker household in Korea and its B/C ratio was estimated about 30 which means high business feasibility. Revenue through furniture remanufacturing also showed 320 times higher than that of SRF production from the perspective of weight. In addition, it is shown that the GHGs reduction from the furniture remanufacturing is 2.2 ton CO2-eq. per year, which is similar to the amount of GHGs absorption effect of 937 pine trees or 622 Korean oak trees annually. Thus the results of this study demonstrate that it is important to adopt an appropriate recycling method considering the economic and environmental effects at the end-of-life stage.

A comparative study of risk according to smoke control flow rate and methods in case of train fire at subway platform (지하철 승강장에서 열차 화재 시 제연풍량 및 방식에 따른 위험도 비교 연구)

  • Ryu, Ji-Oh;Lee, Hu-Yeong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.4
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    • pp.327-339
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    • 2022
  • The purpose of this study is to present the effective smoke control flow rate and mode for securing safety through quantitative risk assessment according to the smoke control flow rate and mode (supply or exhaust) of the platform when a train fire occurs at the subway platform. To this end, a fire outbreak scenario was created using a side platform with a central staircase as a model and fire analysis was performed for each scenario to compare and analyze fire propagation characteristics and ASET, evacuation analysis was performed to predict the number of deaths. In addition, a fire accident rate (F)/number of deaths (N) diagram (F/N diagram) was prepared for each scenario to compare and evaluate the risk according to the smoke control flow rate and mode. In the ASET analysis of harmful factors, carbon monoxide, temperature, and visible distance determined by performance-oriented design methods and standards for firefighting facilities, the effect of visible distance is the largest, In the case where the delay in entering the platform of the fire train was not taken into account, the ASET was analyzed to be about 800 seconds when the air flow rate was 4 × 833 m3/min. The estimated number of deaths varies greatly depending on the location of the vehicle of fire train, In the case of a fire occurring in a vehicle adjacent to the stairs, it is shown that the increase is up to three times that of the vehicle in the lead. In addition, when the smoke control flow rate increases, the number of fatalities decreases, and the reduction rate of the air supply method rather than the exhaust method increases. When the supply flow rate is 4 × 833 m3/min, the expected number of deaths is reduced to 13% compared to the case where ventilation is not performed. As a result of the risk assessment, it is found that the current social risk assessment criteria are satisfied when smoke control is performed, and the number of deaths is the flow rate 4 × 833 m3/min when smoke control is performed at 29.9 people in 10,000 year, It was analyzed that it decreased to 4.36 people.

Germinated Rhynchosia nulubilis Hydrolysate Ameliorates Dexamethasone-induced Muscle Atrophy by Downregulating MAFbx Expression in C2C12 Cells and C57BL/6 Mice (발아 서목태 가수분해물의 근위축 억제 효과)

  • Won Keong Lee;Eun Ji Kim;Sang Gon Kim;Young Min Goo;Young Sook Kil;Seung Mi Sin;Min Ju Ahn;Min Cheol Kang;Young-Sool Hah
    • Journal of Life Science
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    • v.33 no.3
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    • pp.277-286
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    • 2023
  • Sarcopenia is the age-related loss of muscle mass and function. It is a natural part of aging and can lead to decreased mobility and increased frailty. The ubiquitin-proteasome pathway, which is involved in muscle protein degradation, is closely linked to sarcopenia. Germinated Rhynchosia nulubilis hydrolysate (GRH) has been reported to have anti-inflammatory and antioxidant properties, but there have been no reports on its inhibitory effect on muscle reduction. However, no study has yet explored the relationship between GRH and muscle loss inhibition. In this study, we evaluated the effects of GRH on muscle atrophy inhibitory activity in dexamethasone (Dexa)-induced muscle atrophy C2C12 myotubes and mouse models. Moreover, we identified a molecular pathway underlying the effects of GRH on skeletal muscle. May Grunwald-Giemsa staining showed that the length and area of myotubes increased in the groups treated with GRH. In addition, the GRH-treated group significantly reduced the expression of muscle ring finger protein 1 and muscular atrophy F-box (MAFbx) in the Dexa-induced muscular atrophy C2C12 model. GRH also improved muscle strength in C57BL/6 mice with Dexa-induced muscle atrophy, resulting in prolonged running exhaustive time and increased grip strength. We found that muscle strengthening by GRH was correlated with a decreased expression of the MAFbx gene in mouse muscle tissue. In conclusion, GRH can attenuate Dexa-induced muscle atrophy by inhibiting the ubiquitin-proteasome pathway via downregulation of the MAFbx gene expression.

Status and Implications of Hydrogeochemical Characterization of Deep Groundwater for Deep Geological Disposal of High-Level Radioactive Wastes in Developed Countries (고준위 방사성 폐기물 지질처분을 위한 해외 선진국의 심부 지하수 환경 연구동향 분석 및 시사점 도출)

  • Jaehoon Choi;Soonyoung Yu;SunJu Park;Junghoon Park;Seong-Taek Yun
    • Economic and Environmental Geology
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    • v.55 no.6
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    • pp.737-760
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    • 2022
  • For the geological disposal of high-level radioactive wastes (HLW), an understanding of deep subsurface environment is essential through geological, hydrogeological, geochemical, and geotechnical investigations. Although South Korea plans the geological disposal of HLW, only a few studies have been conducted for characterizing the geochemistry of deep subsurface environment. To guide the hydrogeochemical research for selecting suitable repository sites, this study overviewed the status and trends in hydrogeochemical characterization of deep groundwater for the deep geological disposal of HLW in developed countries. As a result of examining the selection process of geological disposal sites in 8 countries including USA, Canada, Finland, Sweden, France, Japan, Germany, and Switzerland, the following geochemical parameters were needed for the geochemical characterization of deep subsurface environment: major and minor elements and isotopes (e.g., 34S and 18O of SO42-, 13C and 14C of DIC, 2H and 18O of water) of both groundwater and pore water (in aquitard), fracture-filling minerals, organic materials, colloids, and oxidation-reduction indicators (e.g., Eh, Fe2+/Fe3+, H2S/SO42-, NH4+/NO3-). A suitable repository was selected based on the integrated interpretation of these geochemical data from deep subsurface. In South Korea, hydrochemical types and evolutionary patterns of deep groundwater were identified using artificial neural networks (e.g., Self-Organizing Map), and the impact of shallow groundwater mixing was evaluated based on multivariate statistics (e.g., M3 modeling). The relationship between fracture-filling minerals and groundwater chemistry also has been investigated through a reaction-path modeling. However, these previous studies in South Korea had been conducted without some important geochemical data including isotopes, oxidationreduction indicators and DOC, mainly due to the lack of available data. Therefore, a detailed geochemical investigation is required over the country to collect these hydrochemical data to select a geological disposal site based on scientific evidence.

Gangneung Haksan Odokttegi Heritage and Performance Contents (강릉학산오독떼기유산과 공연콘텐츠)

  • Lee, Chang-Sik
    • (The) Research of the performance art and culture
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    • no.38
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    • pp.249-275
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    • 2019
  • Gangneung farm song is important for the ritualistic labortheatricals. Especially, in the theatrical process program, the songsof weeding, such as Haksan Odokkteggi and Ssadae, were alsoincluded to represent the agricultural ritualistic prayer for goodharvest. The use of Gangneung farm song is attractive in termsofthe circumstances. There is no chance of success as a plan simplyfor local events. As a comprehensive art, Gangneung farmsongshould simultaneously revitalize locality, representability andglobality. In this context, three directions are suggested dependingon the development progress. The second direction to the thirddirection are mainly oriented toward government-local authoritycentered support, but, in particular, the third direction should aimtobe an open archive in which the public and the contents prosumercan participate. In the production of the traditional content, OSMUmust be endlessly recreated and spread through 'diversity' and'interrelationships'. The contents utilization was discussed based on the transmissiondetails and analysis evidence of Gangneung Haksan Odokttegi. Thediversification of the way of performing farm song and the folk songs that can induce interest were proposed. Furthermore, basedon the fact that 12 songs classified into 8 work types, there-creation of the contents that focus on the playful aspect of theperforming arts was also proposed. In addition to suggestingthedesirable discourse of the performance groups, the experienceprogram development, education, public relations andcommunication reinforcement based on the narrating principlesoffarm songs, and the development and execution of farmsongprograms based on the tradition and the event demands wereproposed. While mentioning the necessity of value creation, thevitality of performing arts skills that put emotion, imagination, fun, sympathy, and etc. on the original form and the model of farmsongs should be supplemented to Gangneung Haksan Odokttegi. The independent transmission aspect of Gangneung Arirangisalso positive. There are difficulties of reduction of traditionalitydueto the designation, standardized transmission, lack of developmentof voluntary performances, and demonstration-centeredtransmission. Narrowly, we focused on the education andvitalization directions in terms of the capacity building of theconservation council itself. By embodying the essential value of theagricultural literature that farm songs possess, it can bringimpression of all worlds, all lives, communication and sharing, anddraw inspiration from the humanistic view of the world andemotion. The reconstitution of agricultural heritage, theconstruction of a storytelling linked with the concrete objects suchas Beomil National Preceptor, Gulsansa, FlagpoleSupport(Dangganjiju), Seokcheon, Hakbawi rock, and etc., andtheestablishment of fusion type farm song museum were proposed. In terms of culture industry, we requested active support fromtheinstitutions including local governments and various farmsongstorytelling creation projects.

Evaluation of the Effects of Hangover-Releasing Agent Containing Vinegar Extract in Common Buckwheat and Tartary Buckwheat on Alcohol Metabolism and Hangover Improvement (일반메밀과 쓴메밀의 식초 추출물의 알코올 대사 및 숙취개선 효능 평가)

  • Su Jeong Kim;Hwang Bae Sohn;A Hyun Park;Jong Nam Lee;Su Hyoung Park;Jung Hwan Nam;Do Yeon Kim;Dong Chil Chang;Yul Ho Kim
    • Korean Journal of Plant Resources
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    • v.36 no.5
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    • pp.435-445
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    • 2023
  • The aim of this study was to explore the effects of vinegar extract from seed of common buckwheat (Fagopyrum esculentum Moench) and seed of tartary buckwheat (F. tataricum Gaertner) on acute ethanol-induced hangover in Sprague-Dawley rats. Vinegar extract from buckwheat is rich choline, quercetin and its glycoside, rutin known as flavonoid antioxidants. The test extract containing buckwheat was proven to alleviate hangovers through a significant reduction in the concentration of alcohol and acetaldehyde in the context of an alcohol-induced hangover model. Hepatic alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) activities were significantly higher in buckwheat vinegar-treated rats than in ethanol-treated rats. Moreover, tartary buckwheat vinegar upregulated antioxidant enzyme such as superoxide dismutase and Catalase activities in liver tissues. These results suggest that buckwheat vinegar extract could alleviate ethanol-induced hangover symptoms by elevating activities related to hepatic ethanol-metabolizing enzymes against ethanol induced metabolites, and in particular, tartary buckwheat should be further developed to be a novel anti-hangover material.

The Effect of Mutual Trust on Relational Performance in Supplier-Buyer Relationships for Business Services Transactions (재상업복무교역중적매매관계중상호신임대관계적효적영향(在商业服务交易中的买卖关系中相互信任对关系绩效的影响))

  • Noh, Jeon-Pyo
    • Journal of Global Scholars of Marketing Science
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    • v.19 no.4
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    • pp.32-43
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    • 2009
  • Trust has been studied extensively in psychology, economics, and sociology, and its importance has been emphasized not only in marketing, but also in business disciplines in general. Unlike past relationships between suppliers and buyers, which take considerable advantage of private networks and may involve unethical business practices, partnerships between suppliers and buyers are at the core of success for industrial marketing amid intense global competition in the 21st century. A high level of mutual cooperation occurs through an exchange relationship based on trust, which brings long-term benefits, competitive enhancements, and transaction cost reductions, among other benefits, for both buyers and suppliers. In spite of the important role of trust, existing studies in buy-supply situations overlook the role of trust and do not systematically analyze the effect of trust on relational performance. Consequently, an in-depth study that determines the relation of trust to the relational performance between buyers and suppliers of business services is absolutely needed. Business services in this study, which include those supporting the manufacturing industry, are drawing attention as the economic growth engine for the next generation. The Korean government has selected business services as a strategic area for the development of manufacturing sectors. Since the demands for opening business services markets are becoming fiercer, the competitiveness of the business service industry must be promoted now more than ever. The purpose of this study is to investigate the effect of the mutual trust between buyers and suppliers on relational performance. Specifically, this study proposed a theoretical model of trust-relational performance in the transactions of business services and empirically tested the hypotheses delineated from the framework. The study suggests strategic implications based on research findings. Empirical data were collected via multiple methods, including via telephone, mail, and in-person interviews. Sample companies were knowledge-based companies supplying and purchasing business services in Korea. The present study collected data on a dyadic basis. Each pair of sample companies includes a buying company and its corresponding supplying company. Mutual trust was traced for each pair of companies. This study proposes a model of trust-relational performance of buying-supplying for business services. The model consists of trust and its antecedents and consequences. The trust of buyers is classified into trust toward the supplying company and trust toward salespersons. Viewing trust both at the individual level and the organizational level is based on the research of Doney and Cannon (1997). Normally, buyers are the subject of trust, but this study supposes that suppliers are the subjects. Hence, it uniquely focused on the bilateral perspective of perceived risk. In other words, suppliers, like buyers, are the subject of trust since transactions are normally bilateral. From this point of view, suppliers' trust in buyers is as important as buyers' trust in suppliers. The suppliers' trust is influenced by the extent to which it trusts the buying companies and the buyers. This classification of trust using an individual level and an organization level is based on the suggestion of Doney and Cannon (1997). Trust affects the process of supplier selection, which works in a bilateral manner. Suppliers are actively involved in the supplier selection process, working very closely with buyers. In addition, the process is affected by the extent to which each party trusts its partners. The selection process consists of certain steps: recognition, information search, supplier selection, and performance evaluation. As a result of the process, both buyers and suppliers evaluate the performance and take corrective actions on the basis of such outcomes as tangible, intangible, and/or side effects. The measurement of trust used for the present study was developed on the basis of the studies of Mayer, Davis and Schoorman (1995) and Mayer and Davis (1999). Based on their recommendations, the three dimensions of trust used for the study include ability, benevolence, and integrity. The original questions were adjusted to the context of the transactions of business services. For example, a question such as "He/she has professional capabilities" has been changed to "The salesperson showed professional capabilities while we talked about our products." The measurement used for this study differs from those used in previous studies (Rotter 1967; Sullivan and Peterson 1982; Dwyer and Oh 1987). The measurements of the antecedents and consequences of trust used for this study were developed on the basis of Doney and Cannon (1997). The original questions were adjusted to the context of transactions in business services. In particular, questions were developed for both buyers and suppliers to address the following factors: reputation (integrity, customer care, good-will), market standing (company size, market share, positioning in the industry), willingness to customize (product, process, delivery), information sharing (proprietary information, private information), willingness to maintain relationships, perceived professionalism, authority empowerment, buyer-seller similarity, and contact frequency. As a consequential variable of trust, relational performance was measured. Relational performance is classified into tangible effects, intangible effects, and side effects. Tangible effects include financial performance; intangible effects include improvements in relations, network developing, and internal employee satisfaction; side effects include those not included either in the tangible or intangible effects. Three hundred fifty pairs of companies were contacted, and one hundred five pairs of companies responded. After deleting five company pairs because of incomplete responses, one hundred five pairs of companies were used for data analysis. The response ratio of the companies used for data analysis is 30% (105/350), which is above the average response ratio in industrial marketing research. As for the characteristics of the respondent companies, the majority of the companies operate service businesses for both buyers (85.4%) and suppliers (81.8%). The majority of buyers (76%) deal with consumer goods, while the majority of suppliers (70%) deal with industrial goods. This may imply that buyers process the incoming material, parts, and components to produce the finished consumer goods. As indicated by their report of the length of acquaintance with their partners, suppliers appear to have longer business relationships than do buyers. Hypothesis 1 tested the effects of buyer-supplier characteristics on trust. The salesperson's professionalism (t=2.070, p<0.05) and authority empowerment (t=2.328, p<0.05) positively affected buyers' trust toward suppliers. On the other hand, authority empowerment (t=2.192, p<0.05) positively affected supplier trust toward buyers. For both buyers and suppliers, the degree of authority empowerment plays a crucial role in the maintenance of their trust in each other. Hypothesis 2 tested the effects of buyerseller relational characteristics on trust. Buyers tend to trust suppliers, as suppliers make every effort to contact buyers (t=2.212, p<0.05). This tendency has also been shown to be much stronger for suppliers (t=2.591, p<0.01). On the other hand suppliers trust buyers because suppliers perceive buyers as being similar to themselves (t=2.702, p<0.01). This finding confirmed the results of Crosby, Evans, and Cowles (1990), which reported that suppliers and buyers build relationships through regular meetings, either for business or personal matters. Hypothesis 3 tested the effects of trust on perceived risk. It has been found that for both suppliers and buyers the lower is the trust, the higher is the perceived risk (t=-6.621, p<0.01 for buyers; t=-2.437, p<0.05). Interestingly, this tendency has been shown to be much stronger for buyers than for suppliers. One possible explanation for this higher level of perceived risk is that buyers normally perceive higher risks than do suppliers in transactions involving business services. For this reason, it is necessary for suppliers to implement risk reduction strategies for buyers. Hypothesis 4 tested the effects of trust on information searching. It has been found that for both suppliers and buyers, contrary to expectation, trust depends on their partner's reputation (t=2.929, p<0.01 for buyers; t=2.711, p<0.05 for suppliers). This finding shows that suppliers with good reputations tend to be trusted. Prior experience did not show any significant relationship with trust for either buyers or suppliers. Hypothesis 5 tested the effects of trust on supplier/buyer selection. Unlike buyers, suppliers tend to trust buyers when they think that previous transactions with buyers were important (t=2.913 p<0.01). However, this study did not show any significant relationship between source loyalty and the trust of buyers in suppliers. Hypothesis 6 tested the effects of trust on relational performances. For buyers and suppliers, financial performance reportedly improved when they trusted their partners (t=2.301, p<0.05 for buyers; t=3.692, p<0.01 for suppliers). It is interesting that this tendency was much stronger for suppliers than it was for buyers. Similarly, competitiveness was reported to improve when buyers and suppliers trusted their partners (t=3.563, p<0.01 for buyers; t=3.042, p<0.01 for suppliers). For suppliers, efficiency and productivity were reportedly improved when they trusted buyers (t=2.673, p<0.01). Other performance indices showed insignificant relationships with trust. The findings of this study have some strategic implications. First and most importantly, trust-based transactions are beneficial for both suppliers and buyers. As verified in the study, financial performance can be improved through efforts to build and maintain mutual trust. Similarly, competitiveness can be increased through the same kinds of effort. Second, trust-based transactions can facilitate the reduction of perceived risks inherent in the purchasing situation. This finding has implications for both suppliers and buyers. It is generally believed that buyers perceive higher risks in a highly involved purchasing situation. To reduce risks, previous studies have recommended that suppliers devise risk-reducing tactics. Moving beyond these recommendations, the present study uniquely focused on the bilateral perspective of perceived risk. In other words, suppliers are also susceptible to perceived risks, especially when they supply services that require very technical and sophisticated manipulations and maintenance. Consequently, buyers and suppliers must solve problems together in close collaboration. Hence, mutual trust plays a crucial role in the problem-solving process. Third, as found in this study, the more authority a salesperson has, the more he or she can be trusted. This finding is very important with regard to tactics. Building trust is a long-term assignment; however, when mutual trust has not been developed, suppliers can overcome the problems they encounter by empowering a salesperson with the authority to make certain decisions. This finding applies to suppliers as well.

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The Benefit of Individualized Custom Bolus in the Postmastectomy Radiation Therapy : Numerical Analysis with 3-D Treatment Planning (유방전절제술 후 방사선치료를 위한 조직보상체 개발 및 3차원 치료계획을 통한 유용성 분석)

  • Cho Jae Ho;Cho Kwang Hwan;Keum Kichang;Han Yongyih;Kim Yong Bae;Chu Sung Sil;Suh Chang Ok
    • Radiation Oncology Journal
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    • v.21 no.1
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    • pp.82-93
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    • 2003
  • Purpose : To reduce the Irradiation dose to the lungs and heart in the case of chest wail irradiation using an oppositional electron beam, we used an Individualized custom bolus, which was precisely designed to compensate for the differences In chest wall thickness. The benefits were evaluated by comparing the normal tissue complication probablilties (NTCPS) and dose statistics both with and without boluses. Materials and Methods : Boluses were made, and their effects evaluated in ten patients treated using the reverse hockey-stick technique. The electron beam energy was determined so as to administer 80% of the irradiation prescription dose to the deepest lung-chest wall border, which was usually located at the internal mammary lymph node chain. An individualized custom bolus was prepared to compensate for a chest wall thinner than the prescription depth by meticulously measuring the chest wall thickness at 1 emf intervals on the planning CT Images. A second planning CT was obtained overlying the individuailzed custom bolus for each patient's chest wall. 3-D treatment planning was peformed using ADAC-Pinnacle$^{3}$ for all patients with and without bolus. NTCPS based on 'the Lyman-Kutcher' model were analyzed and the mean, maximum, minimum doses, V$_{50}$ and V$_{95}$ for 4he heari and lungs were computed. Results .The average NTCPS in the ipsliateral lung showed a statistically significant reduction (p<0.01), from 80.2${\pm}$3.43% to 47.7${\pm}$4.61%, with the use of the individualized custom boluses. The mean lung irradiation dose to the ipsilateral iung was also significantly reduced by about 430 cGy, Trom 2757 cGy to 2,327 cGy (p<0.01). The V$_{50}$ and V$_{95}$ in the ipsilateral lung markedly decreased from the averages of 54.5 and 17.4% to 45.3 and 11.0%, respectively. The V$_{50}$ and V$_{95}$ In the heart also decreased from the averages of 16.8 and 6.1% to 9.8% and 2.2%, respectively. The NTCP In the contralateral lung and the heart were 0%, even for the cases with no bolus because of the small effective mean radiation volume values of 4.4 and 7.1%, respectively Conclusion : The use of an Individualized custom bolus in the radiotherapy of postrnastectorny chest wall reduced the NTCP of the ipsilateral lung by about 24.5 to 40.5%, which can improve the complication free cure probability of breast cancer patients.