• Journal of Communications and Networks
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• v.13 no.1
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• pp.32-42
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• 2011

Frequency reuse among relay stations (RSs) in a down-link access zone is widely adopted for throughput enhancement in IEEE 802.16j relay networks. Since the areas covered by the RSs or the base station (BS) may overlap, some mobile stations (MSs) at the border between two neighboring transmitting stations (RS or BS) using an identical frequency band may suffer severe interference or outage. This co-channel interference within the cell degrades the quality of service (QoS) fairness among the MSs as well as the system throughput. Exclusive use of a frequency band division (orthogonal resource allocation) among RSs can solve this problem but would cause degradation of the system throughput. We observe a trade-off between system throughput and QoS fairness in the previously reported schemes based on frequency reuse. In this paper, we propose a new frequency reuse scheme that achieves high system throughput with a high fairness level in QoS, positioning our scheme far above the trade-off curve formed by previous schemes. We claim that our scheme is beneficial for applications in which a high QoS level is required even for the MSs at the border. Exploiting the features of a directional antenna in the BS, we create a new zone in the frame structure. In the new zone, the RSs can serve the subordinate MSs at the border and prone to interference. In a 3-RS topology, where the RSs are located at points $120^{\circ}$ apart from one another, the throughput and Jain fairness index are 10.64 Mbps and 0.62, respectively. On the other hand, the throughput for the previously reported overlapped and orthogonal allocation schemes is 8.22 Mbps (fairness: 0.48) and 3.99 Mbps (fairness: 0.80), respectively. For a 6-RS topology, our scheme achieves a throughput of 18.38 Mbps with a fairness of 0.68; however, previous schemes with frequency reuse factors of 1, 2, 3, and 6 achieve a throughput of 15.24 Mbps (fairness: 0.53), 12.42 Mbps (fairness: 0.71),8.84 Mbps (fairness: 0.88), and 4.57 Mbps (fairness: 0.88), respectively.

• Journal of the Korean School Mathematics Society
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• v.10 no.4
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• pp.505-518
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• 2007

The purpose of this paper is to investigate the meaning of assessment for students, parents and mathematics teachers in middle school mathematics. For this purpose, we made an inspection to find out how the students grasped assessment results of mathematics, an investigation on the parents questionnaire to catch their viewpoints about assessment in school mathematics. Then, we interviewed three students, three teachers to confirm or to supplement the collected data. From the analyzing of data, we found the followings: First, it is not reasonable to evaluate the middle school students' mathematics accomplishment level using only paper test score. Second, almost all parents focus on their interesting to mathematics test score of their children not any other factors, such as intellectual accomplishment. Third, mathematics teachers claim that private education for only the mathematics test score can block the improving of students' mathematical thinking and application ability of mathematical knowledge.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.185-192
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• 2010

The acoustic vowel space has been used as an acoustic parameter in dysarthric speech. The aim of this work was to examine mathematical formulae for acoustic vowel space and to apply these to Korean speakers with idiopathic Parkinson's disease(IPD). Five acoustic parameters were chosen from earlier works and one new parameter was proposed, the pentagonal vowel space. The six parameters included triangular vowel space (3 area), irregular quadrilateral vowel space (4 area), irregular pentagonal vowel space (5 area), vowel articulatory index (VAI), formant centralization ratio (FCR) and F2i/F1u ratio (F2 ratio). An experimental group of 32 IPD patients(male:female=16:16) and a control group of twenty healthy people (male:female=8:12) participated in the study and repeated vowels (/a-i-u-e-o/) three times. A correlation analysis was performed among the six parameters, 2-way ANOVA was done with gender and groups as independent factors, and an independent sample t-test was conducted between the male and the female group as post hoc comparison. All parameters were highly correlated with each other and only the FCR showed a high negative correlation with the others. The results of ANOVA showed a significant difference in F2 ratio, 3 area, 4 area and 5 area between gender and in 4 area and 5 area between groups. For the male members of the two groups, significant statistical differences were found in all parameters whereas no such differences were found for the female members. These findings indicated that the vowel space of the female group was wider than the vowel space of the male group. These differences may have been caused by gender-specific speech styles rather than by patho-physiological mechanisms. We also claim that the pentagonal vowel space is better than the other vowel spaces at representing the disordered speech in natural speech situations.

• Journal of the Korean Society for Library and Information Science
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• v.52 no.1
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• pp.179-202
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• 2018

The public lending right is a system in which government provide compensation to authors on the premise that the sale of books is reduced due to the book borrowing of the library. Recently, the claim that the public lending right should be introduced in Korea has been continuously raised by the authors. This study was conducted as part of the basic work to demonstrate whether the claims of public lending right are based on reasonable premises. The library's popular lending books and bookstore bestseller books were compared to analyze the similarities and differences. Through this process, we derive necessary factors to prove the validity of the introduction of the public lending right and suggest follow - up study. In addition, we recalled the social meaning of book lending in libraries.

• Journal of Korea Port Economic Association
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• v.18 no.2
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• pp.65-90
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• 2002

Despite the importance and necessity, the 3PL has not been activated to date. Among many views, customers claim that logistics service provider(LSP) are not prepared or capable of offering satisfactory 3PL services, while LSP emphasize the lack of mutual trust, closed corporate culture of the customer and excessive demand for reducing the costs. With this keeping in mind, it surveyed difference of perception between users and providers of 3PL services in terms of the actual status of using 3PL services, the degree of satisfaction and key factors for selecting 3PL provider through the questionnaire. As shown in this study, 43.3％ of the respondents outsourced logistics services. However, Most company outsourced only inland transportation (49.5％) which is a simple and limited scope of 3PL services, but it also indicated that the percentage of users have ranged was less then 10% in outsourcing their whole logistics sector to 3PL provider and employing other logistics functions. Among respondents, a majority of the service provider stated that they offered satisfactory cost-saving to the customers, while users felt that the degree of satisfaction for using 3PL services was evaluated as at an average level and they more highly regarded the strong partnership of their 3PL provider rather than the saving of cost and improvement of customer's services. Moreover, in contrast to the 3PL providers which regard the most important factor for selecting 3PL service provider is the logistics cost quoted, users of 3PL services felt that the quality of services was more significant than the reduction of cost, and this tendency for selecting 3PL providers was shown in more advanced countries. While users of 3PL services indicated that the main reason for not using 3PL services was to avoid disclosing information of their business and it costs much for employing 3PL providers than doing themselves, 3PL providers thought it was due to reluctancy of opening information and resistance from the logistics division engaged in logistics activities concerned. Accordingly, providers and users of 3PL services should trust each other and prepare plan to activate 3PL services under the collaborative relationships as soon as possible.

• Health Policy and Management
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• v.29 no.2
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• pp.228-236
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• 2019

Background: This study investigates the impact of weekend admission with a patient safety indicator (PSI) on 30-day mortality among long-term insurance beneficiaries. Methods: Data were obtained from the National Health Insurance Service-Senior claim database from 2002 to 2013. To obtain unbiased estimates of odds ratio, we used a nested case-control study design. The cases were individuals who had a 30-day mortality event after their last medical utilization, while controls were selected by incidence density sampling based on age and sex. We examined the interaction between the main independent variables of weekend admission and PSI by categorizing cases into four groups: weekend admission/PSI, weekend admission/non-PSI, weekday admission/PSI, and weekday admission/non-PSI. Results: Of the 83,400 individuals in the database, there were 20,854 cases (25.0%) and 62,546 controls (75.0%). After adjusting for socioeconomic, health status, seasonality, and hospital-level factors, the odds ratios (ORs) of 30-day mortality for weekend admission/PSI (OR, 1.484; 95% confidence interval [CI], 1.371-1.606) and weekday admission/PSI (OR, 1.357; 95% CI, 1.298-1.419) were greater than for patients with weekday admission/non-PSI. Conclusion: This study indicated that there is an increased risk of mortality after weekend admission among patients with PSI as compared with patients admitted during the weekday without a PSI. Therefore, our findings suggest that recognizing these different patterns is important to identify at-risk diagnosis to minimize the excess mortality associated with weekend admission in those with PSI.

• Journal of Physiology & Pathology in Korean Medicine
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• v.34 no.6
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• pp.279-284
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• 2020

The theory of "eccentric diseases are generally due to phlegm (怪病多屬痰)" means that phlegm is a major cause for intractable diseases including cerebrovascular accident, depression, insanity, and shock from strange things or evil sprint. It has been a key foundation for the diagnosis and treatment of phlegm in traditional Korean medicine. However, the origin of the theory is not clear and controversial. In this study, we critically reviewed the origin and developing process of the theory in the viewpoints of philology and pathology in Korean medicine. Wang Yin-Jun (王隱 君) did not claim that eccentric diseases are generally due to phlegm in Taidingyangshengzhu-lun (泰定養生主論). The miscitation by following medical literature caused the misunderstanding in the meaning of Taidingyangshengzhu-lun, that phlegm can cause variable symptoms and signs. In the Ming dynasty, some poor medical doctors had tended to diagnose any difficult case as phlegm syndrome and to use Kuntan-huan (滾痰丸) as a standard herbal formula for treating phlegm syndrome. However, the tendency to categorize delicate cases easily to phlegm syndrome is not desirable. Besides, the tendency to use Kuntan-huan as a basic formula for the phlegm syndrome might cause diverse and severe adverse effects. Thus, we cannot accept the theory of eccentric diseases is generally due to phlegm without a doubt. In conclusion, this theory might be a valuable aphorism in terms of considering the possibility of the secondary pathologic factors including phlegm and blood stasis which should be considered first in case of intractable diseases.

• Journal of Practical Agriculture & Fisheries Research
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• v.8 no.1
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• pp.73-96
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• 2006

Today, producers of ginseng spray prohibited fertilizers or use excessive amount of fertilizers whereas distributers either claim that they are selling domestic ginseng when in fact they are selling imported ginseng, cheat on the age or weight of ginseng, or mix domestic and imported ginseng. In terms of quality in comparison with foreign ginseng, 90% of the people surveyed responded that domestic ginseng is more efficacious. When asked whether they would purchase foreign ginseng products when they become available in the market, only one of the respondents responded that he or she would purchase foreign ginseng whereas 50 respondents or 81% of the total surveyed responded that they wouldn't purchase foreign ginseng. About half of the respondents answered that when Chinese red ginseng, ginseng, or wild ginseng products cultivated with harmful fertilizers become available in the market, they would either reconsider purchasing ginseng products or stop purchasing ginseng products all together. In order to develop the ginseng industry 20 respondents (25%) chose the establishment of the standards, 33 respondents (42%) chose marking the place of origin, 15 respondents (19%) quality improvement, 7 respondents (9%) research on the efficacy, and 4 respondents (5%) said improvement on the storage methods as the important factors of the ginseng industry. Considering the fact that 77% of the respondents selected either the standardization or marking of the place of origin, the consumers seem to be demanding reliability in the distribution of ginseng products. Therefore, those people who work in the industry such as the producers, distributors and others should have a sense of mission to develop ginseng, which is a gift from God, and do their best to produce and distribute ginseng products.

• Safety and Health at Work
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• v.14 no.2
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• pp.229-236
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• 2023

Background: In workers with moderate to severe work-related traumatic brain injury (wrTBI), this study aimed to investigate the effect of the timing of rehabilitation therapy initiation on the length of hospital stay and the factors that can influence this timing. Methods: We used data obtained from the Republic of Korea's nationwide Workers' Compensation Insurance. In the Republic of Korea, between the years 2010 and 2019, a total of 26,324 workers filed a claim for compensation for moderate to severe wrTBI. Multiple regression modeling was performed to compare the length of hospital stay according to the timing of rehabilitation therapy initiation following wrTBI. According to the timing of the initiation of rehabilitation therapy following TBI, the proportions of healthcare institutions that provided medical care during each admission step were compared. Results: The length of hospital stay for workers who started rehabilitation therapy within 90 days was significantly shorter than that for workers who started rehabilitationment were first admitted to tertiary hospitals. Approximately 39% of patients who received delayed rehabilitation treatment were first admitted to general hospitals, and 28.5% were first admitted to primary hospitals. Conclusions: Our findings demonstrate the importance of early rehabilitation initiation and that the type of healthcare institution that the patient is first admitted to after wrTBI may influence the timing of rehabilitation initiation. The results of this study also emphasize the need to establish a Worker's Compensation Insuranceespecialized rehabilitation healthcare delivery system.

• Dementia and Neurocognitive Disorders
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• v.22 no.2
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• pp.49-60
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• 2023

Background and Purpose: The National Responsibility Policy for Dementia Care was implemented in September 2017 in Korea. This study aimed to compare dementia incidence in Seoul and Gangwon-do before and after the implementation of this policy. Methods: We extracted insurance claim data from the Korean Health Insurance Review and Assessment Service for people diagnosed with diabetes, hypertension, or dyslipidemia for the first time in Seoul and Gangwon-do, Korea. We defined two enrollment groups based on the policy implementation date: 1) January 1, 2015 to December 31, 2016 (Index 1, pre-implementation), and 2) January 1, 2017 to December 31, 2018 (Index 2, post-implementation). Each group was followed up for 1 year from the time of enrollment. Then, we calculated hazard ratios to compare the incidence of dementia between the two groups, and between Seoul and Gangwon-do. Results: In Seoul, the incidence of dementia was significantly lower in Index 2 than in Index 1 (hazard ratio [HR], 0.926; 95% confidence interval [CI], 0.875-0.979). However, the incidence rate did not differ between the 2 groups (HR, 1.113; 95% CI, 0.966-1.281) in Gangwon-do. In Index 1, the incidence of dementia did not differ between Seoul and Gangwon-do (HR, 1.043; 95% CI, 0.941-1.156), but in Index 2, was significantly higher in Gangwon-do than in Seoul (HR, 1.240; 95% CI, 1.109-1.386). Conclusions: After implementing the National Responsibility Policy for Dementia Care, the dementia incidence rate decreased significantly in Seoul, consistent with other studies, but not in Gangwon-do.