• Korean Journal of Digital Imaging in Medicine
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• v.15 no.1
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• pp.1-7
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• 2013

Purpose : The Carotid Angio inspection including Aortic arch applied to wide area is conducted as the Contrast Enhance MR Angiography(CEA) which is using a contrast medium. However it is a burden not only for someone such as infants, pregnant women and patients suffering from kidney failure but continuous use of contrast medium also can be a burden for patients who has been taken follow up inspection since diagnose lesion already. The purpose of this study is to estimate a usefulness of the Time of Flight (TOF) by comparing with CEA. Materials and methods : 10 patients with an average age of 58 (from 45 to 75) who had MRA inspection in our hospital were studied using 3.0 Tesla Aachieva (Philips, Netherland) MRI system and Sense Neuro-Vascular 16 Channels Coil. The same patient was inspected both TOF and CEA simultaneously. The TOF inspection included from Aortic arch to Willis Circle by connecting 3 TOF stacks and so did CEA inspection. The quantitative analysis was conducted through signal to noise ratio(SNR) and contrast to noise ratio(CNR) with soft tissue by setting up an area of interest on CCA bifurcatoin, ICA, ECA, MCA and VA concerning obtained image. In case of qualitative analysis, 3 radiological technologists and 1 radiologist evaluated 4 items (1: Visibility of the blood vessel, 2: Image distortion measure, 3: Overlapping measure with vein, 4: Peripheral blood vessel description measure) into five points scale (1: Very bad, 2: Bad, 3: Normal 4: Good, 5: Very good). Results : Results for the quantitative analysis was obtained by calculating the average of 5 ROIs in case of SNR and CNR separately. Results of SNR, TOF were generally measured higher than CEA (In case of TOF were 166.1, 205.2, 154.39, 172.23, 161.95, and CEA were 92.05, 95.43, 84.76, 73.69, 88.3). But according to the result of CNR, both TOF and CEA were measured similarly as 67.62, 106.71, 55.9, 73.74, 63.46 for TOF and 67.82, 71.19, 60.52, 49.45, 64.07 for CEA. Throughout every results of each ROI, SNR showed statistically meaningful consequence (0.050.05). In case of qualitative analysis the average of each evaluated item was 4.2points and 4.28points in the item1, 2.93points and 4.55points in the item2, 4.6points and 3.13points in the item3, 2.88points and 4.6points in the item4. According to the results TOF was measured higher in the item3 while in the item2 and item4 CEA was higher and in case of the item1, both CEA and TOF were similar. To sum up statistically meaningful results (p<0.05) were shown in the item2, item3 and item4 but not in the item1 (p>0.05). Conclusions : Both TOF and CEA are complementary because each inspection has pros and cons, but when inspect wide area including Aortic arch normally CEA is conducted. But TOF inspection also can be considered as alternative in terms of patients who has difficulty in the contrast medium such as infants, pregnant women and patients suffering from kidney failure and patients during follow up.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.686-691
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• 2005

We are concerned with the question of servicing warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it by a new item. In this paper, we consider the repair-replacement strategies based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair-replacement decision. Illustrative numerical examples are presented. We also propose a dynamic strategy by taking the expected remaining warranty cost into consideration.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.3
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• pp.25-35
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• 1993

Economic screening procedures using a correlated variable are proposed to assure that the proportion of conforming items is above a desired level after screening. It is assumed that the performance variable and the screening variable are jointly normally distributed. Two screening procedures are considered. In the first screening procedure, all of the items are inspected on the screening variable. If an item fails to meet the screening specifications, it is rejected and excluded from shipment without inspection of the performance variable. In the second screening procedure, the item which fails to meet the screening specifications is inspected on the performance variable. If the value of the performance variable is within specifications the item is accepted, and the item is rejected otherwise. Cost models are constructed which involve cast from an accepted nonconforming item, cost from a rejected item, and quality inspection cost. Methods of finding optimal cutoff value on a screening variable are presented and numerical examples are given.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.4
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• pp.341-348
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• 2005

This paper is concerned with the question of servicing warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it with a new item. In this paper, we consider repair-replacement strategies based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair-replacement decision. Illustrative numerical examples are presented. We also propose a dynamic strategy by taking the expected remaining warranty cost into consideration.

• Journal of the Korean Operations Research and Management Science Society
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• v.25 no.3
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• pp.41-48
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• 2000

We consider the question of warranties for repairable items. During the warranty period, each time an item fails the manufacturer has the obligation to restore the item to operational condition either by repairing the item or by replacing it by a new item. In this paper, we consider a warranty policy for making this decision based on the condition of the failed item. For products with phase-type lifetime distributions where the phases represent the condition of the item, we develop algorithms to determine the expected cost of servicing a warranty and use it in making the repair/replacement decision. illustrative numerical examples are presented.

• Journal of the Korean Home Economics Association
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• v.44 no.4 s.218
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• pp.175-190
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• 2006

The purpose of this research is to investigate consumers' experience of using Internet used-item markets in order to determine their motives in such activity. In terms of the Internet used-item market, (1) it contributes to a sound culture of consumption by recycling, (2) as a C2C market, it retains characteristics fundamentally different from the existing one-way type of market, (3) and it offers different characteristics from existing offline-based flea markets. Two significant themes emerged from the study results. First, users of Internet used-item markets passed through various stages such as novice, addict, and expert and learned the techniques for utilizing the used-item market. Second, for fast transactions with generalized Internet banking and the increasing trend for price bargaining emotional exchange among members is being transformed into the pursuit of transactional efficiency.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.10 no.16
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• pp.129-132
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• 1987

Multi-item inventory problems can be well characterized by the nature of interaction of the quantities and timing. This interaction may be due to the effect of certain combination of orders. It is that the set-up cost of ordering individual items can be saved by jointly ordering at a time. This study finds a decision criteria of optimum inventory policy through the comparisons of individual multi-item order policy(IMP), joint multi-item order policy(JMP), augmented multi-item order policy(AMP) in cost ratio. Subsequently we assume that there exists a unique optimum order level corresponding to an optimum reorder range for the augmented multi-item order, at which a cost saying is maximum.

• Journal of information and communication convergence engineering
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• v.17 no.2
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• pp.135-141
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• 2019

Collaborative filtering algorithms often encounter data sparsity issues. To overcome this issue, auxiliary information of relevant items is analyzed and an item attribute matrix is derived. In this study, we combine the user-item attribute preference with the traditional similarity calculation method to develop an improved similarity calculation approach and use weights to control the importance of these two elements. A collaborative filtering algorithm based on user-item attribute preference is proposed. The experimental results show that the performance of the recommender system is the most optimal when the weight of traditional similarity is equal to that of user-item attribute preference similarity. Although the rating-matrix is sparse, better recommendation results can be obtained by adding a suitable proportion of user-item attribute preference similarity. Moreover, the mean absolute error of the proposed approach is less than that of two traditional collaborative filtering algorithms.

• The Korean Journal of Emergency Medical Services
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• v.5 no.1
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• pp.37-51
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• 2001

This study is aimed at examining the ethical values of EMT students. The results below are based on the revised questionnaires, which can be applicable to EMT from the original questionnaires developed by Lee(1990), with a sample of 124 students consisting of 63 first and 61 second year students, conducted November 2-8, 2001. Data were analyzed using SPSS in terms of means, standard deviations, t-test, ANOVA, Pearson's correlation coefficient. The results are as follows: 1. In the area of Human life, all subjects showed utilitarian disposition. All respondents perceived the item "When patients recognizing there is no hope for survival ask for euthanasia, it is ethically right to accommodate their opinions." as the most utilitarian item, whereas they perceived the item "When an hopeless patient is on cardiac arrest, it is ethically right to do CPR as the most deontoogical item. 2. In the area of patient relationship, all students of two groups took on deontoogical characteristics, but there were no statistically significant differences between two groups. All students perceived an item "EMT have to keep it secret if patients disclose their suicide intentions and ask for absolute secrecy" the most utilitarian item, whereas they perceived an item "Even though patients act and speak in a very rude manner, EMT people should do their best to provide care for patients." as the most deontoogical item. 3. In the area of task relationship, first year students perceived an item "Given time limitations, it is ethically right to give priority to the patients who can be rehabilitated over the patients who can't be fully recovered." as the most utilitarian item, whereas second year students perceived an item "Under no circumstances should any placebo be administered to patients." as the most utilitarian item. All students perceived an item "When EMT students see an unconscious person lying in the street, they have to give him/her emergency treatment." as the most deontoogical item. 4. In the area of coworker relationship, all students of two groups took on deontoogical disposition, but there were no significant differences between two groups. All students of two groups perceived an item "Suppose you are regarded as the person who would be promoted. However, you think that your coworker is more competent than you. In that case you should tell your supervisor about your coworker." as the most utilitarian item. First year students perceived an item, whereas second year students perceived an item "When you observe coworkers' misconduct at work, it is ethically right to ignore their misdeeds." as the most deontoogical item. 5. This study demonstrated that for the first year students, there is a correlational relationship between areas of human life and task relationship, and between areas of task relationship and coworker relationship, whereas for the second year students, there is a correlational relationship between areas of human life and task relationship. 6. In areas of human life and task relationship, there are significant differences according to attitudes toward EMT and attendance at ethics training sessions. In the area of coworker relationship, there are significant differences according to religion, attendance at ethics training sessions, and a code of ethics. Recommendations for future research, 1. Sample items to measure ethical values and the instrument tailored to the needs of EMT should be developed. 2. A longitudinal study to track ethical value changes according to the amount of work experience is needed. 3. A code of ethics and/or ethics training, which could apply in actual situations, should be implemented.

• Journal of Global Scholars of Marketing Science
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• v.17 no.3
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• pp.133-151
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• 2007

The purpose of this article is to examine the effects of item parceling on the consistency of significance testing of the causal parameters with regard to the relationship between the relevant constructs, as well as the effects of the item parceling on the goodness-of-fit indices of LISREL's general models. Most of the researchers' major purpose of using structural equation modeling (SEM) is to test their research hypotheses associated with the causal parameters. Therefore, we investigated three general models of LISREL, rather than the frequently used confirmatory factor analytic (CFA) models by many other researchers. The results of the study showed that there was a high level of consistency in the calculated test statics of causal parameters between the item-parceled solutions and the item-level solutions, and that the item-parceled solutions had better goodness-of-fit indices, such as GFI, AGFI, CFI, and NFI, than the solutions at the item level. However, in terms of RMSEA, there was no such tendency.