• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.1
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• pp.102-108
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• 2000

This paper presents a result of practical study about the adjustment of load correlation equation for the load management of pole transformer. For adjusting the load correlation equation, we analyze the correlative relation between working electric energy[kWh] and peak load[A]. To enhance the accuracy of correlation equation, we classify the 12 representative area patterns. And then, we select the 24 sample pole transformer for each area pattern. For the reliability of the data using the load correlation equation, load management equipment is utilized for each sample pole transformer. Through the on-line data acquisition, we construct the database. For adjusting the load correlation equation, we consider the two points. One is the goodness of fitness for load correlation equation and the other is prevention of pole transformer damage due to the overload. Finally, we propose the correlation equation using the linear and quadratic equation all at once. Through the case studies, we verify that the proposed load correlation equation is reduced the error ratio than conventional correlation equation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.75-84
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• 2014

In order to solve the problems such as overload, single point of failure, non-optimized data path, and network scalability in conventional central mobility management protocols, distributed mobility management schemes have been continually studied in and around the IETF. In this paper, a network-based partially-distributed mobility management mechanism, pDMMv6, is suggested and the performance comparison with traditional protocols such as PMIPv6 and MIPv6 is made through simulation under the various user traffic environment. The simulation results include UDP packet delivery ratio, end-to-end packet delay, binding delay for registration signaling, CPU utilization in each node, and response delays in several server-client TCP applications such as web browsing, e-mail, telnet remote login, FTP file up/down-load, and database access.

• Clinical and Experimental Pediatrics
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• v.63 no.8
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• pp.314-320
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• 2020

Background: The accumulation of unpaired α-globin chains in patients with β-thalassemia major may clinically create ineffective erythropoiesis, hemolysis, and chronic anemia. Multiple blood transfusions and iron overload cause cellular oxidative damage. However, α-tocopherol, an antioxidant, is a potent scavenger of lipid radicals in the membranes of red blood cells (RBCs) of patients with β-thalassemia major. Purpose: To evaluate the effects of α-tocopherol on hemolysis and oxidative stress markers on the RBC membranes of patients with β-thalassemia major. Methods: Forty subjects included in this randomized controlled trial were allocated to the placebo and α-tocopherol groups. Doses of α-tocopherol were based on Institute of Medicine recommendations: 4-8 years old, 200 mg/day; 9-13 years old, 400 mg/day; 14-18 years old, 600 mg/day. Hemolysis, oxidative stress, and antioxidant variables were evaluated before and after 4-week α-tocopherol or placebo treatment, performed before blood transfusions. Results: Significant enhancements in plasma haptoglobin were noted in the α-tocopherol group (3.01 mg/dL; range, 0.60-42.42 mg/dL; P=0.021). However, there was no significant intergroup difference in osmotic fragility test results; hemopexin, malondialdehyde, reduced glutathione (GSH), or oxidized glutathione (GSSG) levels; or GSH/GSSG ratio. Conclusion: Use of α-tocopherol could indirectly improve hemolysis and haptoglobin levels. However, it played no significant role in oxidative stress or as an endogen antioxidant marker in β-thalassemia major.

• Journal of Oral Medicine and Pain
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• v.42 no.4
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• pp.89-101
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• 2017

Purpose: The purpose of this study is to investigate the prevalence of temporomandibular disorders (TMDs) in children and adolescents, their characteristic contributing factors, the characteristic features of symptoms and symptoms, and the response to treatment. Methods: We studied the researches, that were the results of the searches for words such as temporomandibular disorder, TMD, children, adolescents, and juvenile through PubMed and DBpia. Results: According to a study conducted in Busan, the ratio of adolescents increased from 18.3% to 21% in 2008 compared to 2000, and the proportion of boys increased from 38.58% to 45.38%. One of the characteristic contributing factors for adolescents is the macrotrauma such as jaw trauma, vehicle accidents, sports, physical abuse, forceful intubation, and third molar extraction. The second is a microtrauma from parafunctional habit such as bruxism, clenching, hyperextension, wind instrument, and fingernail biting that can cause joint overload, cartilage breakdown, synovial fluid alterations, and other changes within the joint. The diagnosis of TMDs in juvenile adolescents is not significantly different from that of adults. Medical history, clinical examination and radiological examinations are required. Conclusions: In the temporomandibular joint history and assessment, all comprehensive dental history examination is required, including head and neck pain, mandibular dysfunction, previous orofacial trauma, history of present illness with an account of current symptoms. For the treatment and management of temporomandibular arthritis in juvenile adolescents, understanding the characteristics of TMDs in juvenile adolescents and thoroughly analyzing appropriate diagnosis and possible contributing factors through comprehensive history taking & examination, conservative treatment, including fast and active cautions education, will be essential.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.687-708
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• 2017

The machine-to-machine (M2M) communication is featured by tremendous number of devices, small data transmission, and large uplink to downlink traffic ratio. The massive access requests generated by M2M devices would result in the current medium access control (MAC) protocol in LTE/LTE-A networks suffering from physical random access channel (PRACH) overload, high signaling overhead, and resource underutilization. As such, fairness should be carefully considered when M2M traffic coexists with human-to-human (H2H) traffic. To tackle these problems, we propose an adaptive Slotted ALOHA (S-ALOHA) and time division multiple access (TDMA) hybrid protocol. In particular, the proposed hybrid protocol divides the reserved uplink resource blocks (RBs) in a transmission cycle into the S-ALOHA part for M2M traffic with small-size packets and the TDMA part for H2H traffic with large-size packets. Adaptive resource allocation and access class barring (ACB) are exploited and optimized to maximize the channel utility with fairness constraint. Moreover, an upper performance bound for the proposed hybrid protocol is provided by performing the system equilibrium analysis. Simulation results demonstrate that, compared with pure S-ALOHA and pure TDMA protocol under a target fairness constraint of 0.9, our proposed hybrid protocol can improve the capacity by at least 9.44% when ${\lambda}_1:{\lambda}_2=1:1$and by at least 20.53% when ${\lambda}_1:{\lambda}_2=10:1$, where ${\lambda}_1,{\lambda}_2$ are traffic arrival rates of M2M and H2H traffic, respectively.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.663-669
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• 2009

In the electrical railway, the increase of tensions in an overhead contact lines is essential to speed-up of train, because current collection quality largely depends on the ratio of a wave propagation speed to a train speed. For Kyungbu high-speed line, a pulley-type tensioning device is required to have a tension variation of maximum 3%. Therefore we developed a pulley-type tensioning device in order to meet tension variation requirement of the high-speed tensioning device. To verify the performance of the developed device, a performance test, overload test and failure test were carried out according to the factory test procedure of the Kyung-Bu High-speed line. Furthermore, we also performed reliability performance through not only a fatigue test in a factory, but also on-line verification test in Chungbuk line for over 1 year. These tests verified that the tensioning device had applicability to a main line.

• Safety and Health at Work
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• v.5 no.1
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• pp.7-12
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• 2014

Background: In Japan, more than 60% of employees are reported to suffer from anxiety and stress. Consequently, Japanese society has begun to address such important issues as psychogenic disability and job-related suicide. Furthermore, given the aging of society and the surge in the number of elderly people requiring care, it is necessary to adequately and proactively support employees who care for their elderly relatives. The purpose of the present study was to investigate caregiver burden in caring for elderly relatives and work-related stress factors associated with mental health among employees. Methods: We studied 722 men and women aged 18-83 years in a cross-sectional study. The K10 questionnaire was used to examine mental health status. Results: The proportion of participants with a high K10 score was 15% (n = 106). Having little conversation with their supervisor and/or coworkers significantly increased the risk of depression [odds ratio (OR) 1.8], as did high job overload (OR 2.7) and job dissatisfaction (OR 3.8), compared with employees who frequently conversed with their supervisor and/or coworkers. Caring for elderly relatives as a prominent characteristic of an employee was a significant risk factor for depression (OR 2.1). Conclusion: The present study demonstrated that employees who were caring for elderly relatives were significantly associated with an increased risk of depression. To prevent depressive disorders, it may be important to focus on reducing the work-caregiving role conflict, as well as enhancing employees' job control and better rewarding their efforts in the workplace.

• Journal of Community Nutrition
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• v.1 no.2
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• pp.140-147
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• 1999

It has been known for some time that elevated body iron could be a risk factor for coronary heart disease. The present study was conducted to determine body iron status and dietary iron intake of patients with myocardial infarction(MI). Seventy five patients from the Chunam area with their first MI history within he past 2 months were recruited. The serum iron concentration, total iron binding capacity(TIBC) and percent transferrin saturation(TS) were selected as indicators of body iron status. Twenty four hour recall was conducted by trained interviewers to asses the dietary intake. Most women (91.3%) showed waist to hip ratio(W/H) greater than 0.85 while 17.3% of men were assessed to have a tendency of abdominal obesity(W/H>0.95). The average BMI of women was 25.80 and that of men was 23.98. The average diet intake of participants was below the recommended dietary allowances (RDA) for most nutrients. He average dietary iron intake was 10.03 mg/day for all subjects while women's iron intake was significantly lower than men's. However, a great proportion of participants (77%) showed a tendency to have normal iron status. About 9% of the participants were assessed as iron deficient and 14% had an iron overload. The mean serum iron concentration was 125 g/dl ranging from 13.3 to 280.6 g/dl. Iron intake from animal sources were significantly associated with body iron status (r=0.257, p=0.026) when TIBC was used as an iron status indicator. When iron status was assessed with TS, it was directly associated with iron intake from animal sources(r=0.278, p=0.05) for he subjects in the normal iron status group. He results of the present study showed that the nutrient intake of Mi patients in Chunan was not quite adequate while iron status was mostly in the normal range. Further studies are needed to investigated whether there is a possible difference in iron metabolism of the MI patients.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.9
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• pp.72-80
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• 2019

In this task, the tool dynamometer design and manufacture, and the Ansys S/W structural analysis program for tool attachment that satisfies the cutting force measurement requirements of the tool dynamometer system are used to determine the cutting force generated by metal cutting using 3-axis static structural analysis and the LabVIEW system. The cutting power in a cutting process using a milling tool for processing metals provides useful information for understanding the processing, optimization, tool status monitoring, and tool design. Thus, various methods of measuring cutting power have been proposed. The device consists of a strain-gauge-based sensor fitted to a new design force sensing element, which is then placed in a force reduction. The force-sensing element is designed as a symmetrical cross beam with four arms of a rectangular parallel line. Furthermore, data duplication is eliminated by the appropriate setting the strain gauge attachment position and the construction of a suitable Wheatstone full-bridge circuit. This device is intended for use with rotating spindles such as milling tools. Verification and machining tests were performed to determine the static and dynamic characteristics of the tool dynamometer. The verification tests were performed by analyzing the difference between strain data measured by weight and that derived by theoretical calculations. Processing test was performed by attaching a tool dynamometer to the MCT to analyze data generated by the measuring equipment during machining. To maintain high productivity and precision, the system monitors and suppresses process disturbances such as chatter vibration, imbalances, overload, collision, forced vibration due to tool failure, and excessive tool wear; additionally, a tool dynamometer with a high signal-to-noise ratio is provided.

• International Journal of Computer Science & Network Security
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• v.23 no.1
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• pp.153-163
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• 2023

This study is situated in the context of intelligent transport systems, where in-vehicle devices assist drivers to avoid accidents and therefore improve road safety. The vehicles present in a given area form an ad' hoc network of vehicles called vehicular ad' hoc network. In this type of network, the nodes are mobile vehicles and the messages exchanged are messages to warn about obstacles that may hinder the correct driving. Node mobilities make it impossible for inter-node communication to be end-to-end. Recognizing this characteristic has led to delay-tolerant vehicular networks. Embedded devices have small buffers (memory) to hold messages that a node needs to transmit when no other node is within its visibility range for transmission. The performance of a vehicular delay-tolerant network is closely tied to the successful management of the nodes' transit buffer. In this paper, we propose a message transit buffer management model for nodes in vehicular delay tolerant networks. This model consists in setting up, on the one hand, a policy of dropping messages from the buffer when the buffer is full and must receive a new message. This drop policy is based on the concept of intermediate node to destination, queues and priority class of service. It is also based on the properties of the message (size, weight, number of hops, number of replications, remaining time-to-live, etc.). On the other hand, the model defines the policy for selecting the message to be transmitted. The proposed model was evaluated with the ONE opportunistic network simulator based on a 4000m x 4000m area of downtown Bouaké in Côte d'Ivoire. The map data were imported using the Open Street Map tool. The results obtained show that our model improves the delivery ratio of security alert messages, reduces their delivery delay and network overload compared to the existing model. This improvement in communication within a network of vehicles can contribute to the improvement of road safety.