• Journal of Communications and Networks
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• v.15 no.1
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• pp.77-86
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• 2013

Cognitive radio (CR) has emerged as one of effective methods to enhance the utilization of existing radio spectrum. Main principle of CR is that secondary users (SUs) are allowed to use the spectrum unused by primary users (PUs) without interfering PU's transmissions. In this paper, PUs operate on a slot-by-slot basis and SUs try to exploit the slots unused by PUs. We propose OSA protocols in the single channel and we propose an opportunistic spectrum access (OSA) protocols in the multi-channel cognitive radio networks with one control channel and several licensed channels where a slot is divided into contention phase and transmission phase. A slot is divided into reporting phase, contention phase and transmission phase. The reporting phase plays a role of finding idle channels unused by PUs and the contention phase plays a role of selecting a SU who will send packets in the data transmission phase. One SU is selected by carrier sense multiple access / collision avoidance (CSMA/CA) with request to send / clear to send (RTS/CTS) mechanism on control channel and the SU is allowed to occupy all remaining part of all idle channels during the current slot. For mathematical analysis, first we deal with the single-channel case and we model the proposed OSA media access control (MAC) protocol by three-dimensional discrete time Markov chain (DTMC) whose one-step transition probability matrix has a special structure so as to apply the censored Markov chain method to obtain the steady state distribution.We obtain the throughput and the distribution of access delay. Next we deal with the multi-channel case and obtain the throughput and the distribution of access delay by using results of single-channel case. In numerical results, our mathematical analysis is verified by simulations and we give numerical results on throughput and access delay of the proposed MAC protocol. Finally, we find the maximum allowable number of SUs satisfying the requirements on throughput and access delay.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.244-250
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• 2015

Survivability is avoidance and tolerance ability of combat systems for accomplishing mission in battle field. Therefore, the combat system has to protect or minimize any damage from threats. For this reason, many modeling and simulation based studies which analyze vulnerability of the combat system by threats, are in progress to improve survivability of the combat system. In this paper, we developed a 3D penetration analysis program for survivability analysis of combat system. To do this, we applied the penetration analysis equation to threat and protection performance of tank. Also we implemented simple tank models based on 3D CAD, and tested the developed program using the implemented tank models. As a result, we verified the developed program that is possible to analyze penetration by threat and protection performance of tank and to visualize its result, based on scenarios.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.2
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• pp.141-152
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• 2021

Purpose: This study aimed to compare the effects of ischemic compression (IC) therapy and extracorporeal shock wave therapy (ESWT) in patients with upper trapezius myofascial pain syndrome and to present an effective treatment method for these patients. Methods: A total of 42 patients with upper trapezius myofascial pain syndrome were randomly assigned to the IC group (n = 21) and ESWT group (n = 21). IC therapy and ESWT were performed in the IC and ESWT groups, respectively. Treatment was applied to the trigger point of the upper trapezius muscle. Visual analog scales (VAS), pain pressure threshold (PPT), range of motion, neck disability index (NDI), and fear-avoidance belief questionnaire (FABQ) were evaluated before and after the intervention to compare its effectiveness. Results: Both groups showed significant differences before and after the intervention in VAS, PPT, NDI, FABQ, flexion, extension, right side bending, and left side bending (p <.05). In addition, there were significant differences in the IC group compared to the ESWT group in VAS, PPT, and NDI (p <.05). Conclusion: IC therapy and ESWT applied to patients with upper trapezius myofascial pain syndrome are mediating methods of pain, function, and psychosocial effects. In addition, IC therapy may be a more effective mediating method for pain and dysfunction than ESWT.

• Journal of Apiculture
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• v.34 no.4
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• pp.315-323
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• 2019

Large amounts of sludge produced by paper mill industries represent one of the most serious environmental problems in the world. Recently, beekeepers living in the neighborhood of the paper mill in Hwasan County, Youngcheon city, GB, Korea, became alarmed that honey bee colonies were dying off suddenly across the neighborhood. A preliminary study was conducted to evaluate the toxicity (oral, fumigation, repellent) of recycled solid paper mill sludge (SPMS) and leachate paper mill sludge (LPMS) to honey bee workers under laboratory conditions, and to analyze the volatile organic compounds(VOC). The SPMS and LPMS were separately subjected to a liquid-liquid extraction (LLE) at three temperatures to extract VOC(highest VOC yields: 1.52% SPMS and 0.34% LPMS). A total of 70 chemicals were detected in the VOC of paper mill sludges, of which 49 and 21 volatile organic compounds from SPMS and LPMS, respectively. The SPMS was dominated by high degree presence of stanols (saturated sterols), such as cholestanol, cholestan-3-ol and also saturated hydrocarbons. However, LPMS was characterized by the absence of sterols. Both SPMS and LPMS showed an influence on the olfactory behavior of honey bee on Y-tube assay, with repulsion rates of 72 and 68%, respectively. Both SPMS and LPMS at concentration of 100mg/mL caused higher honey bee oral mortality than the untreated controls at 48, 72, 96 and 120 hours after treatment(highest oral mortality at 120 hr: 85.74%(SPMS); 93.51 % (LPMS)). A similar pattern was observed when honey bees were tested to fumigant toxicity. Both SPMS and LPMS caused significant higher mortality than the untreated control 24 hour after the exposure (highest fumigation mortality at 120 hr: 69.4% (SPMS); 56.8% (LPMS)). These preliminary results indicated that paper mill sludge could be partly responsible for sudden death and disappearance of honey bees, especially in hot humid summer days. With climate change, the risk of environmental chemical exposure to honey bee would pose greater attention.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.1
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• pp.49-61
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• 2021

PURPOSE: Hamstring muscle shortening is related to low back pain, and it is important to check the hamstring muscle flexibility and pelvic mobility to analyze the effects of the intervention. This study examined the effects of hamstring muscle shortening on flexibility and pelvic mobility according to the method of stretching the hamstring muscle in patients with low back pain. METHODS: Forty Low Back Pain Patients participated. The subjects performed the Visual Analogue Scale (VAS), Fear Avoidance Belief Questionnaire (FABQ), Korean version of Oswestry Disability Index (KODI), Myovision, and sensbalance therapy cushion (pelvic mobility, proprioception). The subjects were divided into two groups to perform the passive and active stretching protocol. The intervention was conducted three times a week for four weeks. RESULTS: Hamstring muscle flexibility was increased significantly in both groups (p < .05), and there was no difference between the groups. VAS, FABQ was decreased significantly in both groups (p < .01), and there was no difference between the groups. The left lower back muscle impedance was decreased significantly in both groups (p < .05). The passive stretching group showed a significant increase in the pelvic anterior, posterior, and left tilt ROM (p < .05). The active stretching group showed a significant increase in the pelvic anterior, posterior tilt ROM (p < .05). CONCLUSION: Both stretching methods may be useful intervention methods for pelvic mobility and pain recovery and can assess back pain recovery.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.10
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• pp.1288-1293
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• 2020

As fears of infection with the Corona 19 virus increase, an untact mood is also blowing in the real estate market. Changes in life style are bringing about changes in the way of life and patterns of consumption. In the real estate marketing market, such changes are inevitable. In particular, marketing using a real estate model house has the characteristics of marketing that is closely related to the denseness that many people visit in an enclosed space. These characteristics include all three features (airtight, dense, close), characteristics mentioned in the COVID-19 prevention rules. Therefore, in this study, we will look at ways to reinforce model house customer marketing in line with the untact (non-face-to-face) trend and to avoid the above three features, characteristics in the model house customer marketing process, and show the implementation results to avoid features. Through this, we propose a safe and expandable real estate marketing strategy through the avoidance of the three features of corona 19.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.5
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• pp.29-41
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• 2022

Alien species cause problems in various ecosystems, reduce biodiversity, and destroy ecosystems. Due to these problems, the problem of a management plan is increasing, and it is difficult to accurately identify each individual and calculate the number of individuals, especially when researching alien turtle species such as GPS and PIT based on capture. this study intends to conduct an individual recognition study using a UAV. Recently, UAVs can take various sensor-based photos and easily obtain high-definition image data at low altitudes. Therefore, based on previous studies, this study investigated five variables to be considered in UAV flights and produced a test paper using them. OCR was used to monitor the displayed turtles using the manufactured test paper, and this confirmed the recognition rate. As a result, the use of yellow numbers showed the highest recognition rate. In addition, the minimum threat distance was confirmed to be 3 to 6m, and turtles with a shell size of 6 to 8cm were also identified during the flight. Therefore, we tried to propose an object recognition methodology for turtle display text using OCR, and it is expected to be used as a new turtle monitoring technique.

• Physical Therapy Korea
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• v.29 no.1
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• pp.54-63
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• 2022

Background: Low back and neck pain are two of the most common medical problems in the adult population. It is estimated that between 70% and 80% adults experience an episode of low back pain at least once during their lifetime. Objects: This study aimed to compare the effects of various stretching exercises and muscle energy techniques used for treatment of iliopsoas, quadratus lumborum, and hamstrings of patients with low back pain. Methods: A total of 52 subjects were randomly assigned to the control group (n = 17), the muscle energy technology group (METG, n = 19), and the stretching exercise group (SEG, n = 16). Interventions were performed twice a week for 4 weeks. Outcomes were measured before and after 4 weeks of treatment in the three groups, using the Korean version of the Oswestry Disability Index, the Visual Analogue Scale (VAS), the Fear Avoidance Belief Questionnaire (FABQ), the Finger to Floor test (FTF), the Modified-Modified Schober Test (MMS), and the Trunk Flexion Range of Motion test. Results: This study showed significant reduction in the pre-test and post-test KODI, VAS, and FABQ scores in all the three groups (p < 0.05). The KODI, VAS, FABQ and FTF assessed in this study showed interactions between the groups and the measurement time point (p < 0.01). After intervention, the KODI, VAS, FABQ and FTF in the SEG and METG were significantly higher (p < 0.05), and there was no difference between the METG and SEG. MMS and HFROM test showed no difference between the three groups (p > 0.05). Conclusion: KODI, VAS, FABQ and FTF showed significant improvement after basic physical therapy, muscle energy technique, and stretching exercise intervention. And there was no significant difference in the intervention effect between the muscle energy group and the stretching exercise group.

• The Journal of Pediatrics of Korean Medicine
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• v.37 no.3
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• pp.1-16
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• 2023

Objectives We aimed to investigate the effectiveness of the Korean medical critical pathway (CP) in treating childhood anorexia. Methods In total, 21 patients who met the criteria and agreed to provide information were assigned to the CP group, while 24 patients who met the criteria, agreed to provide information, but disagreed with CP application were assigned to the non-CP group. Demographic, clinical, and economic indices were compared between the two groups. Clinical indices before and after treatment were also compared between the two groups. Results In the CP group, height, weight, body mass index (BMI), BMI percentile, and food approach (FAP) increased significantly after treatment, and numeric rating scale (NRS) and food avoidance (FAV) scores decreased significantly. In the non-CP group, height, weight, weight percentile, BMI, BMI percentile, and FAP increased significantly, whereas NRS and FAV decreased significantly after treatment. Compared to the non-CP group, CP application increased FAP and decreased FAV, medical expenses per consultation, and the total treatment period. Conclusions The application of the Korean medical critical pathway for childhood anorexia is an effective cure system that decreases overall medical expenses with good-quality treatment by means of the standardization of medical practices.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.161-162
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• 2020

Major advanced ports around the world are preparing for environmental regulations such as increased efficiency of ports and low emission of pollutants in ports by utilizing fourth industrial technologies and ICT technologies such as AI, big data, self-driving cars and connected cars. It is also investing in developing fully unmanned terminals to solve the problem of workforce reduction caused by avoidance of 3D industries. However, the introduction of advanced technology is being delayed in domestic ports, which has led to a drop in port efficiency. In addition, port safety accidents have also occurred frequently, seriously affecting port marketing. Thus, the characteristics and types of each container terminal in Korea were analyzed and the factors for introducing autonomous cooperative driving were classified into five section factors and 15 division factors. Hierarchically classified factors will be surveyed on workers working in shipping lines, port construction, container terminals and related ministries.