• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.125-132
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• 2023

To NP-complete 3-SAT problem, this paper proposes a O(nm) polynomial time algorithm, where n is the number of literals and m is the total frequency of all literals in equation f. Conventionally well-known DPLLs should perform O(2^𝑙) in the worst case by performing backtracking if they fail to find a solution in a brute-force search of a branch-and-bound for the number of literals 𝑙. DPLL forms the core of the SAT Solver by substituting true(T) or false(F) for a literal so that a clause containing the least frequency literal is true(T) and removing a clause containing that literal. Contrary to DPLL, the proposed algorithm selects a literal _max𝑙 with the maximum frequency and sets $_{\max}({\mid}l{\mid},{\mid}{\bar{l}}{\mid})=1$. It then deletes 𝑙∈c_i clause in addition to ${\bar{l}}$ from ${\bar{l}}{\in}c_i$ clause. Its test results on various k-SAT problems not only show that it performs less than existing DPLL algorithm, but prove its simplicity in satisfiability verification.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.85-99
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• 2023

By the social advancement, radiological disaster prevention planning is getting important considering complex disasters as in the Fukushima radiological disaster occurred by a chain of natural disasters. However, it has yet to be suggested the specific prevention plans for the complex disasters in the field of national radiological disaster prevention. This study aims to analyze the types of complex disasters in order to select the ones that are relatively more likely to occur in the domestic environment. It is also to analyze the impact on the radiological disaster prevention by searching damage spread of the classified natural disasters. We provides the necessary criterial for establishing disaster prevention plans through the scenarios for radiological emergency responses based on complex disasters. it is thought that these criteria can help prepare for the worst case scenario and implement effective resident protection.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.84-90
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• 2018

We researched the way to minimize the damage when the chlorine-leak accident take place in a purification plant. Since the level of risk based on the Off-site Risk Assessment(ORA) is a combination of proportional to the number of residents in the damaged area and frequency of accidents, we suggested the adequate conditions to reduce the number of residents in the damaged area by means of the operating temperature of a handling facility, installation of a emergency shut-off valve, and the analysis of the variation of the damaging range in accordance with the type of enclosure. The coverage of damage was calculated by the 'KORA(Korea Off-site Risk Assessment Supporting Tool) program. The research shows that the lower operating temperature gets, the more emergency shut-off valve being installed and the higher enclosure level of facility becomes, the extent of damage gets decreased. The decreasing rate of worst case was 17.6%, 71%, 34.5% respectively, the decreasing rate of alternative case was 31.6%, 69.0%, 34.8% respectively.

• Korean Journal of Acupuncture
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• v.29 no.3
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• pp.385-395
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• 2012

Objectives : Meridian sinew theory was introduced in Miraculous Pivot, Huangdi's Internal Classic, to explain in relation with locations of meridian sinews, causes, mechanisms, and treatment of diseases. The meridian sinews are understood to include muscles, tendons and ligaments, or muscles in the superficial body made up with muscles, ligaments, tendons, fascia etc. This theory shows the similarity or organic relationship between the meridian sinews and muscles. From the Hippocrates(460-385 BC) ages, traction therapy was used as a treatment method on muscular diseases such as low back pain, scoliosis, etc in western medicine. The effects of traction therapy, however, were unclear so that this study was purposed to illustrate the effectiveness of continuous traction therapy and to develop meridian sinews treatment. Methods : We made 2 hypotheses to explain the cause of scoliosis occurrence, muscles contraction and relaxation. As the hypothesis, we made the spinal model having 3 joints with wood and rubber bands. Each of the three joints in the spinal model represents the case of normal(NT; control), contraction(AT 1)and relaxation(AT 2) condition, and distance between the vertebrae joints was measured. Results : Under normal circumstance models, the normal type 1(NT 1; muscle relax state) and normal type 2(NT 2; muscle contract state) all joints were being towed equally. But in an unusual contracted situation, regardless of the relationship of joint area, contracted part of joint was not released. And in a relaxed situation, regardless of joint areas, released parts of joint were further released. These observation results mean that the effects of traction might be different from the purpose of traction therapy of Hippocrates. Conclusions : To explain the effect of traction therapy for scoliosis, the spinal cord model and scoliosis model were made. After vertebral bodies were pulled with different tensile forces, we compared the observed length of the each joints pulled. The results suggested that there were no effects of traction in objected parts with traction method from Hippocrates' design, continuous traction method. Moreover, it may worsen the symptom in worst case. Of course, our results are just the result of experimental models and clinical results may be different. More careful studies, therefore, are required.

• Journal of Educational Research in Mathematics
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• v.26 no.4
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• pp.791-818
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• 2016

This case study is performed to check the validity of cognitive behavioral therapy for high school students with mathematics anxiety. In order to find out whether it is effective or not, one female high school student who suffers physically and mentally from mathematics anxiety was selected and cognitive behavioral therapy was applied. The therapy is applied to her for 30 to 40 minutes, once a week, and for eight weeks. The main themes were: To understand my problem, To write down thinking log, To set up a plan for actions, To experiment actions, To change intermediate confidence, To change core belief. To check the validity, before and after the experiment, revised version of Heo(1996)'s assessment tools for mathematics anxiety was applied. The subject was interviewed and the results of the therapy were compared and analyzed. According to the research, the worst mathematics anxiety of the subject was test anxiety. After the procedure, the anxiety related to mathematics and teachers was lessened. Especially, the subject had changed her mind and become more positive and optimistic on solving difficult mathematics problems. Therefore, the effectiveness of cognitive behavioral therapy on mathematics anxiety was confirmed. It is required to construct special program - about cognitive behavioral therapy, interactions of cognitive-affective causes, and group therapy - and check the validity of it.

• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.147-156
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• 2005

CGI is a standard interface rule between web server and gateway devised for the gateway's standard output to replace a static web document in UNIX environment. So, it is common to use standard I/O statements provided by the programming language for the CGI gateway. But the standard I/O mechanism is one of buffer strategies that are designed transparently to operating system and optimized for generic cases. This means that it nay be useful to apply another optimization to the standard I/O environment in CGI gateway. In this paper, we introduced standard output method and file output method as the two output optimization areas for CGI gateways written in C language in the UNIX/LINUX systems, and applied the proposed methods of each area to Debian LINUX, IBM AIX, SUN Solaris, Digital UNIX respectively. Then we analyzed the effect of them focused on execution time. The results were different from operating system to operating system. Compared to normal situation, the best case of standard output area showed about $10{\%}$ improvement and the worst case showed $60{\%}$ degradation in file output area where some performance improvements were expected.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.267-273
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• 2012

The short-range communication module was developed in this paper which is suitable for the point-to-multipoint circumstances of 40 terminals communicating frequently in about 50 meters. The media access control layer of this communication module using asynchronous time-division multiplexing provides a fast and robust performance even in the worst case of simultaneous transmission events, and low packet error rate was measured a in LOS (Line-of-sight) circumstance by adding the function of acknowledge response to media access control layer. The difference test was carried out in order to measure the performance of point-to-multipoint communication. Two communication modules are respectively measured and graphed in 10 branches to 40 branches. The communication module developed in this paper showed a faster performance than the commercial Zigbee module in the specific case presented in this paper. Especially, in over 20 branches showed wide differences of the transmission speed. This results is caused by more network overhead of Zigbee whose wider applications needs the network layer and applicaiton layer besides media access control layer. Also, the asynchronous time-division multiplexing proposed in this paper are more suitable than CSMA-CA of Zigbee module when a lot of module ought to be frequently communicated in small area.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.6
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• pp.25-37
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• 2000

The trajectories of feature points can be defined by the correspondences between points in consecutive frames. The correspondence problem is known to be difficult to solve because false positives and false negatives almost always exist in real image sequences. In this paper, we propose a robust feature tracking algorithm considering incomplete trajectories such as entering and/or vanishing trajectories. The trajectories of feature points are determined by calculating the matching measure, which is defined as the minimum weighted Euclidean distance between two feature points. The weights are automatically updated in order to properly reflect the motion characteristics. We solve the correspondence problem as an optimal graph search problem, considering that the existence of false feature points may have serious effect on the correspondence search. The proposed algorithm finds a local optimal correspondence so that the effect of false feature point can be minimized in the decision process. The time complexity of the proposed graph search algorithm is given by O(mn) in the best case and O($m^2n$) in the worst case, where m and n arc the number of feature points in two consecutive frames. By considering false feature points and by properly reflecting motion characteristics, the proposed algorithm can find trajectories correctly and robustly, which has been shown by experimental results.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.412-417
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• 2012

Mucopolysaccharidosis (MPS) is a disorder which is caused by the defect of the lysosomal enzyme that is essentially needed for resolution of glycosaminoglycans (GAGs). Metabolite of GAGs will accumulate in the lysosome of cells and will result in the dysfunction of cells, tissues, and organs. Eventually, patients will manifest both mental retardation and physical disorders. In worst cases, mucopolysaccharidosis can cause premature death. The current clinical types have been classified as MPS from type I to type IX according to the defect of certain enzyme. The dental complications have been reported as delay of eruption, enamel hypoplasia, microdontia, malocclusion, condylar defects, gingival hyperplasia and dentigerous cystlike follicle. This clinical report presents the case of a boy with MPS type II, Hunter Syndrome which has various dental complications.

• Fire Science and Engineering
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• v.31 no.2
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• pp.119-126
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• 2017

This study examined the soundness, vibration, and size of ambulances currently used in Korea as well as the comfort and convenience of ambulancesin Korea. The target vehicles were measured and investigated using the currently used freight type, van type, and Benz ambulance. Currently, the ambulance standards in Korea have only formal production standards, and there is no regulation on safety for ambulances, space regulation for first aid, comfort, and convenience. Therefore, comparative experiments on the comfort and convenience were measured using noise and vibration measurement experiments, and research was conducted on the size and interior rearrangement of ambulances to investigate the areas that can improve the comfort and convenience. The noise measurementsshowed that the noise was large in the order of the van type, Benz type, and freight type. In the case of a speed of 40 km/h or more, the noise measurement result was 60 to 70 dB or more. In the case of vibration, the Benz type and van type ambulance were good, and the vibration of the freight type showed the worst result, highlighting the need for improvement. Lastly, it is not possible to increase the internal size of the structure of domestic ambulance. On the other hand, it is important that through ambulance relocation and the position of first aid personnel, it will be possible to use it more comfortably and conveniently.