• The KIPS Transactions:PartD
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• v.9D no.2
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• pp.203-214
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• 2002

This paper presents a physical database design methodology for spatial access structures using transformation techniques in spatial database systems. Recently, many spatial access structures have been proposed in the literature. However, there has been no effort for their physical database design. We first show that most spatial queries in the original space are transformed into one type of range queries in the transform space, and then propose a method for finding the optimal configuration of spatial access structures by using the relationship between the shapes of query regions, that are correspond to the range queries, and page regions, that are correspond to data pages, in the transform space. For performance evaluation, we perform extensive experiments with the MBR-MLGF, a spatial access structure using transformation techniques, using various types of queries and data distributions. The results indicate that our proposed method builds optimal MBR-MLGF according to the query types. When the interval ratio of a transformed four-dimensional query region is 1 : 16 : 256 : 4096, the performance of the proposed method is enhanced by as much as five times over that of the conventional cyclic splitting method. The result confirms that the proposed physical database design methodology is useful in a practical way.

• The KIPS Transactions:PartD
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• v.9D no.2
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• pp.235-242
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• 2002

We propose an advanced transaction scheduling protocol for concurrency control of multilevel secure databases in wireless mobile network environment. Wireless communication is characterized by frequent spurious disconnections. So short-lived transaction must quickly access database without any delay by long-lived one. We adapted two-phase locking protocol, namely traditional syntax-oriented serializability notions, to multilevel secure databases in wireless mobile network environment. Altruistic locking, as an advanced protocol, has attempted to reduce delay effect associated with lock release moment by use of the idea of donation. An improved form of a1truism has also been deployed for extended a1truistic locking. This is in a way that scope of data to he early released is enlarged to include even data initially not intended to be donated. Our protocol is based on extended altruistic locking, but a new method, namely bi-directional donation locking for multilevel secure databases (MLBiDL), is additionally used in order to satisfy security requirements and concurrency. We showed the Simulation experiments that MLBiDL outperforms the other locking protocols in terms of the degree of throughput and average waiting time.

• Journal of the Korea Society of Computer and Information
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• v.20 no.4
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• pp.131-138
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• 2015

One of the most conspicuous characteristics of a business model that pursues expanding customer relationship is that it tries to lock in customers by encouraging them to repeat purchase in the long-term with the help of "Follow" function in Social Networking Service (SNS), which enables producers to automatically register the customers as potentially important ones and to offer them customized marketing services. In the value chain of the agriculture sector, producers of agricultural products can use SNS functions to provide loyal customers with valuable information and experiences such as the real-time information of their farm and products, hidden stories about the whole process from seeding to harvesting, and the storage and cooking methods of their products. These activities help the producers invoke customers' desire to live in the farm and to grow the products themselves. They also raise the accessibility of the producers' websites as customers are able to share a variety of news and knowledge such as the release of new products. This means that the producers's websites are now functioning to enable the producers to perform sales and promotion related activities. It is a big leap from the traditional e-commerce business model where sales and promotion of a product were separated and could be connected only through outside links. This two-way, viral characteristics of marketing services using SNS facilitate customers to share product information and their purchase experience with each other, which leads to more effective and efficient communication within the customer community.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.6
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• pp.136-150
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• 2010

Due to the effect of indoor coverage problem, the QoS of the indoor users will be degraded dramatically, with the number of indoor users. The femto cell is a popular solution for such problems. Since the price of the femto base station is usually cheap enough, one can sets up huge number of base stations in a small indoor area to reduce the size of communication cell. In this way, the QoS of the indoor users can be improved significantly. Moreover, the data rate can also be increased. However, how to decide an ideal transmitting power according to the surrounding radio environment is not a trivial problem, that still has not been addressed well. If the transmit power of femto base station is too large, the interference to the macro users will be increased. Conversely, if the transmit power of femto base station is too small; the coverage of femto base station will be reduced. To address this problem, we propose a power configuration method in femto base station using Genetic Algorithm by investigating a new fitness function. Furthermore, we adopt the weighted sum approach to improve the user performance in different modes. The simulation results show that the proposed power configuration method can not only improves the downlink SINR, but also enhance the channel capacity for both the Macro cell systems and Femto cell systems compared with some conventional methods.

• Journal of the Korean GEO-environmental Society
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• v.21 no.9
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• pp.25-32
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• 2020

The underground utilities installed under the ground is an important civil engineering structure, such as water supply and sewerage pipes, underground power lines, various communication lines, and city gas pipes. Such underground utilities can be exposed to risk due to external factors such as concentrated rainfall and vehicle load, and it is important to select and construct an appropriate backfill material. Currently, a method mainly used is to fill the soil around the underground utilities and compact it. But it is difficult to compact the lower part of the buried pipe and the compaction efficiency decreases, reducing the stability of the underground utilities and causing various damages. In addition, there are disadvantages such as a decrease in ground strength due to disturbance of the ground, a complicated construction process, and construction costs increase because the construction period becomes longer, and civil complaints due to traffic restrictions. One way to solve this problem is to use a liquid filler. The liquid filler has advantages such as self-leveling ability, self-compaction, fluidity, artificial strength control, and low strength that can be re-excavated for maintenance. In this study, uniaxial compression strength test and fluidity test were performed to characterize the mixed soil using marine clay, stabilizer, and in-situ soil as backfill material. A freezing-thawing test was performed to understand the strength characteristics of the liquid filler by freezing, and in order to examine the effect of the filling materials on the corrosion of the underground pipe, an electrical resistivity test and a pH test were performed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.432-441
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• 2017

The aim of this study was to investigate the relationship among family function, intimacy risk with the opposite sex, and campus life satisfaction among college students. A descriptive study was conducted. Data were collected from May 11, 2017 to May 20, 2017 by using a structured questionnaire. The participants were 180 college students at two colleges in J-city. Data were analyzed using t-test, one way ANOVA, Scheffe test, pearson correlation coefficient, and multiple regression analysis with SPSS 20.0. The mean scores were as follows: family function $3.07{\pm}0.44$(5 points), intimacy risk with the opposite sex $2.03{\pm}0.59$(4 points), and campus life satisfaction $3.20{\pm}0.50$(5 points). There was a significant correlation between the family function, intimacy risk with the opposite sex, and campus life satisfaction variables. Multiple regression analysis showed that factors influencing campus life satisfaction were family communication(${\beta}=0.341$, p=.001) and parental economic activity type(${\beta}=0.161$, p=.007). The explanation power of this regression model was 13.1%. These results of this study indicate that effective campus life satisfaction should be developed by including improvement of family community of family function.

• Korean Medical Education Review
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• v.13 no.1
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• pp.25-34
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• 2011

Modern medicine has early experienced the absence of mimesis and has been trying to replace the absence with objective grounds and experimental data. However, as medicine became science, the crisis of medicine spread more widely. Microscopic powers and violences are invisible, but individuals are powerless and vainly unable to resist. The anguish or introspection about the situation is sometimes described in stories such as An Engagement by Lee Eung Jun. An Engagement is mentioned in this article due to the writer's attitude, which shows his introspection and desire for harmony through the wounds of each trivial character. The writer is unceasingly talking about suffering people in his story and his seriousness enables readers to find his stronger sympathy over life and death than in any other medical stories. In fact, it is impossible for readers to comprehend the confusing propositions which the writer pours out, and even uncomfortable to read the story. Nevertheless, the propositions are always in contact with reality. Perhaps it is not the writer's confusing propositions that make us uncomfortable. It might be ourselves who are always alienated and starved. We can say that the characters' pains and wounds are phantom pains caused by the absence of mimesis. Since there is no affected area, their pains cannot be measured by only scientific medicine. However, the current medical profession regards objective research evidences as absolute truth and allows them to be the sole criterion. Although scientific skills such as DNA analysis and MRI scan can be the substitutes for doctors' judgment, so much of medicine is still interpersonal relationships. An Engagement. As a person promises to marry another, as all beings together in the world promise to subordinate to one another, every subject is consistently a valuable part of each other for the writer's eyes. He is aware that it is originally impossible to get engaged to the world, but he does not give up the possibility of genuine communication. In today's post-modernism society, where a large number of pathological views define the members and the world itself, endless questioning of existence and digging into pathology will be the only way to reduce the gap between individuals and their world. This article does not say that a literary work will lead the change of medical paradigm. It sprang from a desire for medical humanities to gain more interest of the medical field, where the encounter between literature and medicine is still unfamiliar, and to make medical education recognize the importance of humanities. Starting with this work, I believe that the humanities will help us to find the solution to the age of absence of mimesis and to the crisis of medicine.

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.59-76
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• 2015

Recent wide spread of embedded devices and technology growth of broadband communication has led to rapid increase in the volume of created and managed data. As a result, data centers have to increase the storage capacity cost-effectively to store the created data. Data deduplication is one way to save the storage space by removing redundant data. This work propose IO extent based deduplication schemes called CORE-Dedup that exploits content-preserving access locality. We acquire IO traces from block device layer in virtual machine host, and compare the deduplication performance of chunking method between the fixed size and IO extent based. At multiple workload of 10 user's compile in virtual machine environment, the result shows that 4 KB fixed size chunking and IO extent based chunking use chunk index 14500 and 1700, respectively. The deduplication rate account for 60.4% and 57.6% on fixed size and IO extent chunking, respectively.

• Journal of Distribution Science
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• v.15 no.6
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• pp.65-76
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• 2017

Purpose - The quality of customer service has been importantly considered as a way of retaining current customers. Recent development of service industry which based on Information & Communication Technology allows firms to utilize different employees for their businesses. Although it is regarded as important to consider emotional labor of employees working for customers in ICT service industry, little was known the role of emotional dissonance. Thus, current paper focused on emotional labor and tried to identify the factors which influence on employees' intrinsic motivation for married women working in call centers. This study highlighted the influence of the emotional dissonance on the employees' intrinsic motivation, and the moderating influences of work-family conflict on the relationship between emotional dissonance and intrinsic motivation. Research design, data, and methodology - The research samples were gathered from seven call centers of Korean financial institutions located in South Korea. The model of emotional dissonance was developed, which emphasizes the influence of emotional dissonance as a predictor on intrinsic motivation, and then the other model was also introduced to explain how employees' intrinsic motivation were aggravated by work-family conflict. To examine these research models, samples were collected from 468 married women working in call centers of Korean financial institutions located in Seoul. A total of 468 samples were used in the analysis after deleting data of missing value. SPSS 22.0 were utilized for data analysis. Results - The results of current study showed that emotional dissonance is negatively related to intrinsic motivation, and there are significant differences in work-family conflict. Those results generally support the proposed hypotheses. Conclusions - These results suggest that the relationship of intrinsic motivation of married women working in call center for customers' service were influenced by emotional dissonance, which outcomes were interacted not by face-to-face contact with their customers, but by emotional contacts. Managerially, these findings suggest the one who emphasize the quality of customer's service of call center need to introduce the programs for minimizing both of emotional dissonance and work-family conflict. These findings also suggest that the service quality via intrinsic motivation of married women working in call center is hard to be accomplished without considering the factors of emotional dissonance and work-family conflict.

• 전자공학회논문지 IE
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• v.44 no.1
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• pp.27-32
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• 2007

This study was to suggest the predictive model of propagation, considering the effect by the multipath waves produced by the sending and receiving vehicles' left/right reflectors and the adjacent vehicles when the communication between the vehicles on the one-way two-lanes road in the urban city with a lot of traffic jams. Then, the radius of curved road was 600[m], the length of curved roads $52.4\sim471.2[m]$, and the bridge's pier of road was $5o\sim45o$. Also, it was simulated by changing the receiving vehicle located on the curved road's gap from minimum 3.3[m] to maximum 29.5[m], corresponding to the change of distance of the bridge's pier of road and curved road. As a result of this research above, in case of $5o\sim15o$ bridge's pier of road, it was within l[dB] regardless of the receiving vehicle's position on the curved road in case of propagation path loss. In case of $15o\sim45o$, it was approximately $1\sim8[dB]$ as the bridge's pier of road is changed. And, in case of propagation path, it found out that it was changed to $0.4\sim120[m]$ according to the change of bridge's pier of road. Then, the delay time of propagation was 400[nsec] as it produced 120[m] in the difference of propagation path.