• Title/Summary/Keyword: analysis within/cross cases

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Exploratory Case Study for Key Successful Factors of Producy Service System (Product-Service System(PSS) 성공과 실패요인에 관한 탐색적 사례 연구)

  • Park, A-Rum;Jin, Dong-Su;Lee, Kyoung-Jun
    • Journal of Intelligence and Information Systems
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    • v.17 no.4
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    • pp.255-277
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    • 2011
  • Product Service System(PSS), which is an integrated combination of product and service, provides new value to customer and makes companies sustainable as well. The objective of this paper draws Critical Successful Factors(CSF) of PSS through multiple case study. First, we review various concepts and types in PSS and Platform business literature currently available on this topic. Second, after investigating various cases with the characteristics of PSS and platform business, we select four cases of 'iPod of Apple', 'Kindle of Amazon', 'Zune of Microsoft', and 'e-book reader of Sony'. Then, the four cases are categorized as successful and failed cases according to criteria of case selection and PSS classification. We consider two methodologies for the case selection, i.e., 'Strategies for the Selection of Samples and Cases' proposed by Bent(2006) and the seven case selection procedures proposed by Jason and John(2008). For case selection, 'Stratified sample and Paradigmatic cases' is adopted as one of several options for sampling. Then, we use the seven case selection procedures such as 'typical', 'diverse', 'extreme', 'deviant', 'influential', 'most-similar', and 'mostdifferent' and among them only three procedures of 'diverse', 'most?similar', and 'most-different' are applied for the case selection. For PSS classification, the eight PSS types, suggested by Tukker(2004), of 'product related', 'advice and consulancy', 'product lease', 'product renting/sharing', 'product pooling', 'activity management', 'pay per service unit', 'functional result' are utilized. We categorize the four selected cases as a product oriented group because the cases not only sell a product, but also offer service needed during the use phase of the product. Then, we analyze the four cases by using cross-case pattern that Eisenhardt(1991) suggested. Eisenhardt(1991) argued that three processes are required for avoiding reaching premature or even false conclusion. The fist step includes selecting categories of dimensions and finding within-group similarities coupled with intergroup difference. In the second process, pairs of cases are selected and listed. The second step forces researchers to find the subtle similarities and differences between cases. The third process is to divide the data by data source. The result of cross-case pattern indicates that the similarities of iPod and Kindle as successful cases are convenient user interface, successful plarform strategy, and rich contents. The differences between the successful cases are that, wheares iPod has been recognized as the culture code, Kindle has implemented a low price as its main strategy. Meanwhile, the similarities of Zune and PRS series as failed cases are lack of sufficient applications and contents. The differences between the failed cases are that, wheares Zune adopted an undifferentiated strategy, PRS series conducted high-price strategy. From the analysis of the cases, we generate three hypotheses. The first hypothesis assumes that a successful PSS system requires convenient user interface. The second hypothesis assumes that a successful PSS system requires a reciprocal(win/win) business model. The third hypothesis assumes that a successful PSS system requires sufficient quantities of applications and contents. To verify the hypotheses, we uses the cross-matching (or pattern matching) methodology. The methodology matches three key words (user interface, reciprocal business model, contents) of the hypotheses to the previous papers related to PSS, digital contents, and Information System (IS). Finally, this paper suggests the three implications from analyzed results. A successful PSS system needs to provide differentiated value for customers such as convenient user interface, e.g., the simple design of iTunes (iPod) and the provision of connection to Kindle Store without any charge. A successful PSS system also requires a mutually benefitable business model as Apple and Amazon implement a policy that provides a reasonable proft sharing for third party. A successful PSS system requires sufficient quantities of applications and contents.

Prediction and Measurement of Residual Stresses in Injection Molded Parts

  • Kwon, Young-Il;Kang, Tae-Jin;Chung, Kwansoo;Youn, Jae Ryoun
    • Fibers and Polymers
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    • v.2 no.4
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    • pp.203-211
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    • 2001
  • Residual stresses were predicted by a flow analysis in the mold cavity and residual stress distribution in the injection molded product was measured. Flow field was analyzed by the hybrid FEM/FDM method, using the Hele Shaw approximation. The Modified Cross model was used to determine the dependence of the viscosity on the temperature and the shear rate. The specific volume of the polymer melt which varies with the pressure and temperature fields was calculated by the Tait\`s state equation. Flow analysis results such as pressure, temperature, and the location of the liquid-solid interface were used as the input of the stress analysis. In order to calculate more accurate gap-wise temperature field, a coordinate transformation technique was used. The residual stress distribution in the gap-wise temperature field, a coordinate transformation technique was used. The residual stress distribution in the gap-wise direction was predicted in two cases, the free quenching, under the assumption that the shrinkage of the injection molded product occurs within the mold cavity and that the solid polymer is elastic. Effects of the initial flow rate, packing pressure, and mold temperature on the residual stress distribution was discussed. Experimental results were also obtained by the layer removal method for molded polypropylene.

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Optimal Structural Design of Composite Helicopter Blades using a Genetic Algorithm-based Optimizer PSGA (유전자 알고리즘 PSGA를 이용한 복합재료 헬리콥터 블레이드 최적 구조설계)

  • Chang, Se Hoon;Jung, Sung Nam
    • Composites Research
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    • v.35 no.5
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    • pp.340-346
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    • 2022
  • In this study, an optimal structural design of composite helicopter blades is performed using the genetic algorithm-based optimizer PSGA (Particle Swarm assisted Genetic Algorithm). The blade sections consist of the skin, spar, form, and balancing weight. The sectional geometries are generated using the B-spline curves while an opensource code Gmsh is used to discretize each material domain which is then analyzed by a finite element sectional analysis program Ksec2d. The HART II blade formed based on either C- or D-spar configuration is exploited to verify the cross-sectional design framework. A numerical simulation shows that each spar model reduces the blade mass by 7.39% and 6.65%, respectively, as compared with the baseline HART II blade case, while the shear center locations being remain close (within 5% chord) to the quarter chord line for both cases. The effectiveness of the present optimal structural design framework is demonstrated, which can readily be applied for the structural design of composite helicopter blades.

Plasma Soluble CD30 as a Possible Marker of Adult T-cell Leukemia in HTLV-1 Carriers: a Nested Case-Control Study

  • Takemoto, Shigeki;Iwanaga, Masako;Sagara, Yasuko;Watanabe, Toshiki
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.18
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    • pp.8253-8258
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    • 2016
  • Elevated levels of soluble CD30 (sCD30) are linked with various T-cell neoplasms. However, the relationship between sCD30 levels and the development of adult T-cell leukemia (ATL) in human T-cell leukemia virus type 1 (HTLV-1) carriers remains to be clarified. We here investigated whether plasma sCD30 is associated with risk of ATL in a nested case-control study within a cohort of HTLV-1 carriers. We compared sCD30 levels between 11 cases (i.e., HTLV-1 carriers who later progressed to ATL) and 22 age-, sex- and institution-matched control HTLV-1 carriers (i.e., those with no progression). The sCD30 concentration at baseline was significantly higher in cases than in controls (median 65.8, range 27.2-134.5 U/mL vs. median 22.2, range 8.4-63.1 U/mL, P=0.001). In the univariate logistic regression analysis, a higher sCD30 (${\geq}30.2U/mL$) was significantly associated with ATL development (odds ratio 7.88 and the 95% confidence intervals 1.35-45.8, P = 0.02). Among cases, sCD30 concentration tended to increase at the time of diagnosis of aggressive-type ATL, but the concentration was stable in those developing the smoldering-type. This suggests that sCD30 may serve as a predictive marker for the onset of aggressive-type ATL in HTLV-1 carriers.

Knowledge and Attitudes of Food Safety among Hospitality and Culinary Students

  • Cha, Myeong-Hwa;Park, Jyung-Rewng
    • Preventive Nutrition and Food Science
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    • v.10 no.1
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    • pp.68-73
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    • 2005
  • A significant number of cases of illness has been attributed to food consumption in restaurants, and as the number of meals eaten away from home continues to rise, the potential for large-scale, foodborne illness outbreaks will continue to increase. It is critical that hospitality and culinary arts students preparing for careers as professionals in foodservice establishments or restaurants have an appropriate understanding of food safety. The level of food safety knowledge was similar between hospitality and culinary arts students, and an analysis of 266 questionnaires indicated that specific areas, such as hand washing, cross contamination in refrigerator, reheating leftovers, refrigeration of cooked food within two hours, proper temperature of food storage, using of thermometers to monitor temperatures, proper egg handling, and possible food borne illness caused by fruits, should be the primary focus of educational resources. Student respondents showed a higher awareness level of responsibility in their roles for food safety, but more emphasis needs to be given to the correct understanding of food safety issues. Hospitality and culinary arts educators can use this precise information to develop food safety education materials and programs to assist in the prevention of foodborne illness and to knowledgeably educate their graduates about food safety.

Analysis of the Types of External Wall and Roof Structure Layer Composition of CLT Building (CLT 건축물의 외벽 및 지붕 구조체 레이어 구성 유형 분석)

  • Yoo, Dong-Wan;Lee, Tae-Goo
    • Journal of the Korean Institute of Rural Architecture
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    • v.22 no.4
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    • pp.71-78
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    • 2020
  • Today, the whole world is going through a big chaos due to the COVID-19, but paradoxically, the emergence of COVID-19 has been leading to the need for sustainable development, such as Green New Deal that can improve global warming and carbon emissions, and the need for sustainable architecture is growing bigger and bigger in the architectural field as well. The level of CLT buildings in Korea is at a very rudimentary stage, while CLT buildings remedying existing wooden buildings are getting the spotlight among European countries for sustainable architecture. This study was conducted to categorize structure layer compositions of overseas CLT buildings and analyze architectural techniques and materials applied by collecting and analyzing information about CLT structure layer compositions of overseas CLT building-related institutions, companies and cases. When classifying structure layer compositions of foreign CLT buildings depending on the roles of layers. it was revealed that exterior wall structure layers were combined and organized within a sequence of external finishing, ventilation, waterproof, board, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing, sloped roof structure layers were external finishing, ventilation, waterproof, board, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing, flat roof structure layers were external finishing, ventilation, waterproof, planking wood, external insulation, waterproof, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing.

Influence of nuclear data library on neutronics benchmark of China experimental fast reactor start-up tests

  • Guo, Hui;Jin, Xin;Huo, Xingkai;Gu, Hanyang;Wu, Haicheng
    • Nuclear Engineering and Technology
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    • v.54 no.10
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    • pp.3888-3896
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    • 2022
  • Nuclear data is the basis of reactor physics analysis. This paper aim at studying the influence of major evaluated nuclear data libraries, CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, and JENDL-4.0u, on the neutronics modelling of CEFR start-up tests. Results show these four libraries have a good performance and consistency in the modelling CEFR start-up tests. The JEFF-3.3 results exhibit only an 8 pcm keff difference with the measurement. The difference in criticality is decomposed by nuclide, which shows the large overestimation of CENDL-3.2 is mainly from the cross-section of 52Cr. Except for few cases, the calculation results are within 1σ of measurement uncertainty in control rod worth, sodium void reactivity, temperature reactivity, and subassembly swap reactivity. In the evaluation of axial and radial reaction distribution, there are about 65% of relative errors that are less than 5% and 82% of relative errors that are less than 10%.

The impact of fuel depletion scheme within SCALE code on the criticality of spent fuel pool with RBMK fuel assemblies

  • Andrius Slavickas;Tadas Kaliatka;Raimondas Pabarcius;Sigitas Rimkevicius
    • Nuclear Engineering and Technology
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    • v.54 no.12
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    • pp.4731-4742
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    • 2022
  • RBMK fuel assemblies differ from other LWR FA due to a specific arrangement of the fuel rods, the low enrichment, and the used burnable absorber - erbium. Therefore, there is a challenge to adapt modeling tools, developed for other LWR types, to solve RBMK problems. A set of 10 different depletion simulation schemes were tested to estimate the impact on reactivity and spent fuel composition of possible SCALE code options for the neutron transport modelling and the use of different nuclear data libraries. The simulations were performed using cross-section libraries based on both, VII.0 and VII.1, versions of ENDF/B nuclear data, and assuming continuous energy and multigroup simulation modes, standard and user-defined Dancoff factor values, and employing deterministic and Monte Carlo methods. The criticality analysis with burn-up credit was performed for the SFP loaded with RBMK-1500 FA. Spent fuel compositions were taken from each of 10 performed depletion simulations. The criticality of SFP is found to be overestimated by up to 0.08% in simulation cases using user-defined Dancoff factors comparing the results obtained using the continuous energy library (VII.1 version of ENDF/B nuclear data). It was shown that such discrepancy is determined by the higher U-235 and Pu-239 isotopes concentrations calculated.

Reconsideration of Clinical and Histopathological Prognostic Factors in Breast Cancer Patients: A Single Center Experience

  • Tanriverdi, Ozgur;Meydan, Nezih;Barutca, Sabri
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.2
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    • pp.807-812
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    • 2014
  • Background: The clinical course of the neoplasm may vary due to both patient and tumor cell characteristics. Aim: The aim of this study was to research the influence of certain clinical and pathological features on the prognosis of early stage breast cancer. Materials and Methods: This study included 117 women that were treated and followed-up in between the years 2001-2011. The demographic, clinical and histopathological features of the cases were reviewed retrospectively. Statistical analysis: In categorical comparisons between groups, cross-tab statistics were provided and significance levels were estimated using chi-square test. Cox regression analysis, Pearson and Spearman correlation tests, and the Kaplan-Meier test were also used. Results: With an average of 35-months follow-up, the mean disease-free survival of patients was 91 months and the mean overall survival time was 132 months. In the whole study group, the disease-free survival rates were 88, 84, 83 and 52%, while the overall survival rates 95, 94, 83, and 83% within the first, third, fifth and tenth years, respectively. The disease-free and overall survival rates were decreased with increasing tumor grades, though this was not statistically significant. The presence of lymphovascular invasion, positive staining with Ki67 and postmenopausal status were associated with shorter disease-free and overall survival times. In multivariate analysis, only age and Her2/neu receptor status influenced the prognosis significantly. Conclusions: In parallel to clinical, histopathological, and immunohistochemical prognostic features in breast cancer, in this study positive Her2/neu receptor status, a previously accepted poor prognostic factor, was found to have positive influence after trastuzumab treatment.

Factors Delaying Presentation of Sudanese Breast Cancer Patients: an Analysis Using Andersen's Model

  • Salih, Alaaddin M;Alfaki, Musab M;Alam-Elhuda, Dafallah M;Nouradyem, Momin M
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.4
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    • pp.2105-2110
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    • 2016
  • Purpose: A multicenter, observational, cross-sectional study was conducted to assess factors delaying presentation of breast cancer cases. Materials and Methods: Data were collected from a pair of highly specialized referral centers, both located in the center of the Sudanese capital, Khartoum. For a total of 153 eligible respondents, durations of delay, clinicodemographic factors and reasons of referral were collected from our respondents through self-administered questionnaires. Logistic regression analysis and ANOVA were used to test the relation between periods of delay and different factors. Odd ratios (OR's) and their correspondent Confidence intervals (95% CI's). Delay periods were studied with Andersen's model. Results: The average duration of delay in our study was 11.9 (${\pm}11.2$) months. Only a quarter of our patients presented early within the first 3 months after onset of their symptoms. About 47.7% arrived later during the course of the first year, while it took beyond that for the last 27% to come. A prior diagnosis of BC was the only predictor of early presentation (for 3-12 months OR=9.6 (p<0.00), 95% CI 9.55-9.75; for >12 months OR=9.3 (p<0.00), 95% CI 9.33-9.33). Out of the 12 different reasons for delay given by our respondents, none showed a significant difference between patients presenting early or late. Financial incapacity (17.5%), ignorance about BC (14.3), and misinterpreting symptoms (12.7%) were the top three whys of delay. Conclusions: Our findings support existence of a non-uniform pattern of delay among Sudanese BC patients. Changing currently adopted awareness elevating strategies into much more inclusive approaches is strongly recommended.