• Molecules and Cells
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• v.20 no.3
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• pp.315-324
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• 2005

Pain is an unpleasant sensation experienced when tissues are damaged. Thus, pain sensation in some way protects body from imminent threat or injury. Peripheral sensory nerves innervated to peripheral tissues initially respond to multiple forms of noxious or strong stimuli, such as heat, mechanical and chemical stimuli. In response to these stimuli, electrical signals for conducting the nociceptive neural signals through axons are generated. These action potentials are then conveyed to specific areas in the spinal cord and in the brain. Sensory afferent fibers are heterogeneous in many aspects. For example, sensory nerves are classified as $A{\alpha}$, $-{\beta}$, $-{\delta}$ and C-fibers according to their diameter and degree of myelination. It is widely accepted that small sensory fibers tend to respond to vigorous or noxious stimuli and related to nociception. Thus these fibers are specifically called nociceptors. Most of nociceptors respond to noxious mechanical stimuli and heat. In addition, these sensory fibers also respond to chemical stimuli [Davis et al. (1993)] such as capsaicin. Thus, nociceptors are considered polymodal. Recent advance in research on ion channels in sensory neurons reveals molecular mechanisms underlying how various types of stimuli can be transduced to neural signals transmitted to the brain for pain perception. In particular, electrophysiological studies on ion channels characterize biophysical properties of ion channels in sensory neurons. Furthermore, molecular biology leads to identification of genetic structures as well as molecular properties of ion channels in sensory neurons. These ion channels are expressed in axon terminals as well as in cell soma. When these channels are activated, inward currents or outward currents are generated, which will lead to depolarization or hyperpolarization of the membrane causing increased or decreased excitability of sensory neurons. In order to depolarize the membrane of nerve terminals, either inward currents should be generated or outward currents should be inhibited. So far, many cationic channels that are responsible for the excitation of sensory neurons are introduced recently. Activation of these channels in sensory neurons is evidently critical to the generation of nociceptive signals. The main channels responsible for inward membrane currents in nociceptors are voltage-activated sodium and calcium channels, while outward current is carried mainly by potassium ions. In addition, activation of non-selective cation channels is also responsible for the excitation of sensory neurons. Thus, excitability of neurons can be controlled by regulating expression or by modulating activity of these channels.

• Journal of the Korean Society of Hazard Mitigation
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• v.6 no.1 s.20
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• pp.29-38
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• 2006

There are increasing needs to provide sufficient information on road directions through road signs for expanding cities and traffic networks. Improving efficiency of direction guidance information from road signs not only requires criteria for but also systematic approach to selecting place names that appear on road signs. As such, this paper looks at road direction information from existing road signs that leads to Suwon and investigates whether the current system of road signs provides efficient, systematic and continuous direction information for road users to easily reach their destination. In this paper, Suwon's city hall is set up as the final destination, which is linked from five other cities, Anyang, Osan, Ansan, Yongin and Seongnam. The paper attempts to find out whether there is continuity and suitable number of road signs for direction information by analyzing the road signs between these 5 cities and Suwon with respect to direction, direction advance notice and direction guidance. It is found that drivers cannot easily find the needed information on their destination from the existing road signs and that continuity of selected place names that systematically appear on road signs is insufficiency. In addition, direction guidance on road signs is problematic, because the appearance frequency of road signs is not adequate and the continuity of road signs is not effective. Moreover, there is insufficient information on local direction guidance for immediate destinations on road signs with respect to turning left or right or going straight.

• The Korean Journal of Air & Space Law and Policy
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• v.28 no.2
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• pp.97-115
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• 2013

The world-wide principal criteria of aircraft operations is ICAO Annex 6. Operations of Aircraft. Among ICAO Annex 6, Part I is for International Commercial Air Transport - Aeroplanes and it assumes major part of civil aviation. ICAO has been providing Contracting States with SARPs(Standards and Recommended Practices) and monitor each State's reflection degree into their domestic air law, so-called USOAP(Universal Safety Oversight Audit Program). Current ICAO USOAP is Snap-shot method, but it will be changed to USOAP-CMA method from the year of 2013. ICAO USOAP results have overall effects on national aviation industry such as routes, insurance, airlines cooperation and so forth. Low grades of results attract international attention and that leads to flag carrier's operation stoppage, route restriction, airlines cooperation restriction, insurance increase directly or indirectly. Thus it is important to get excellent grades in ICAO USOAP and to maintain confidence. Our government ranked top to get 98.89 grades in 2008 ICAO USOAP but after 2008 the revised provisions have not been reflected sufficiently into our air law. So I would like to grip reflection ratio of ICAO Annex 6 Part I into our domestic air law by using the most updated revised edition on this paper. Together I would like to suggest alternatives for the non-reflected and partially reflected.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.914-923
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• 2015

Recently, as the number of smart devices (such as smart TV or Web based IPTV) increases, the way of digital broadcast contents is changed. This change leads that conventional broadcast media accepts Web platform and its services to provide more quality contents. Based on this change, in education field, education broadcasting also follows the trend. The traditional education broadcasting platforms, which just delivered the lecture in one-way, are utilized the Web technology to make interaction between teacher and student. Current education platforms, however, are insufficient to satisfy users' demands for two-way interactions. This paper proposes a new remote collaborative learning platform which able to provide high interactivity among users. Based on new functional requirements from original use case, the platform provides collaborative contents sharing and collaborative video streaming techniques by utilizing WebRTC (Web Real-Time Communication) technology. The implementation demonstrates the operability of proposed system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.835-842
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• 2016

In Korea, urban railway cars are typically maintained using the strategy of predictive maintenance. In an effort to overcome the limitations of the existing strategy, there is increased interest in adopting the condition-based maintenance strategy. In this study, a novel method is proposed to detect faults in the solenoid valves of the braking system in urban railway vehicles. We determined the key component (i.e., solenoid valve) that leads to braking system faults through the analysis of failure modes, effects, and criticality. Then, an equivalent circuit model was developed with the compensation of the temperature effect on solenoid coils. Finally, we presented how to detect faults with the equivalent circuit model and current signal measurements. To demonstrate the performance of the proposed method, we conducted a case study using real solenoid valves taken from urban railway vehicles. In summary, it was shown that the proposed method can be effective to detect faults in solenoid valves. We anticipate the outcome from this study can help secure the safety and reliability of urban railway vehicles.

• Journal of Science and Technology Studies
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• v.14 no.2
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• pp.127-164
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• 2014

This essay examines the motivations, goals, and assumptions of those who are participating in the appropriate technology movement in contemporary South Korea. In addition to analyzing books, articles, presentation materials, and media reports written by or about the "appropriate technologists," I have interviewed a few of them to hear their thoughts on appropriate technologies as well as inappropriate technologies. They choose to work on appropriate technology out of their good will for people in need, their Christian faith, and their pride in Korea's rapid and successful development. As a result, the appropriate technology movement in Korea does not engage in a critical evaluation of current sociotechnical systems, but instead takes an ethical and paternalistic stance in accepting and improving the given situation. Its apolitical character is effective in drawing a large number of participants, but it also limits their imagination and the movement's potential influence. Moreover, the movement's focus on "the other 90%" leads the participants to frame appropriate technology as something for "them" or "locals" rather than as something for "all of us." This essay concludes by suggesting that the appropriate technology movement in Korea should expand its scope from an ethical pursuit of technology to a political engagement with technology.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.125-135
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• 1993

The safe and efficient operation of nuclear plants is recognized to be accomplished through the application of plant automation using digital technology, which is one of main targets of the next generation nuclear plants. For plant level automation, it is first required that each major subsystem be digitalized, and the steam generator water level control system is discussed in this study. The transfer functions between inputs and the level are derived by employing the thermal hydraulic model of the steam generator and are applied to the analysis of the current three-element control system. Since the control scheme in this study includes the steam generator itself as a process plant, the system order is high and the numerical instability arises in digitalizing. Together with this, the unreliability of the feedwater feedback signal at low power level leads to the proposal of a two-element control system with a proper digital controller. The digital PI controller developed for this system has the initial power adaptive gain and integration time constant. And it makes the overall system response satisfy the stability and other necessary control specifications simultaneously. Since the two-element control system using this controller depends on the initial power only, it is simple to define and it shows a similar level response behavior to that of its corresponding analog system.

• Journal of the Korean Electrochemical Society
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• v.7 no.1
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• pp.38-43
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• 2004

Porous carbon aerogel-silica gel composite materials were used as the electrodes of capacitive deionization(CDI) process, which were prepared by a paste rolling method. The electrochemical parameters such at current values, coulombs af a function of cycle, and CDI efficiencies were investigated for 10th and 100th cycles in 1,000ppm NaCl solution. Carbon aerogel-silica gel composite electrodes showed good wet-ability and higher mechanical strengths even under the NaCl solutions as well. In our experimented runs, all of the composite electrodes also are showed good cycle-ability without destroy of active material during cycles and decreased manufacturing times by $50\%$. Conclusively, the adding of silica gel powder to carbon aerogel leads to the effective performance of CDI process due to effective utilization of active materials by increasing the wet-ability and mechanical hardness.

• Journal of Korean Society of Transportation
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• v.28 no.5
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• pp.141-153
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• 2010

The study is about the development of operating speed prediction models aimed for an evaluation of design consistency of four lane rural roads. The main differences of this study relative to previous research are the method of data collection and classification of road alignments. The previous studies collected speed data at several points in the horizontal curve and approaching tangent. This method of collection is based on the assumption that acceleration and deceleration only occurs at horizontal tangents and the speed is kept constant at horizontal curves. However, this assumption leads to an unreliable speed estimation, so drivers' behavior is not well represented. Contrary to the previous approach, speed data were collected with one and data analysis using a speed profile is made for data selection before building final models. A total of six speed prediction models were made according to the combination of horizontal and vertical alignments. The study predicts that the speed data analysis and selection for model building employed in this study can improve the prediction accuracy of models and be useful to analyze drivers' speed behavior in a more detailed way. Furthermore, it is expected that the operating speed prediction models can help complement the current design-speed-based guidelines, so more benefits to drivers as real road users, rather than engineers or decision makers, can be achieved.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.643-664
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• 1997

This study is to provide evidence-based recommendations for the most-effective treatments of benign prostatic hyperplasia based on patient preference or clinical need, and to meta-analyze the Korean literatures for the development of BPH treatment guidelines. For these analyses, extensive literature searches (208 articles), with priority given to the Korean Journal of Urology, were conducted from 1960 to August, 1996. Meta-analysis, like all statistical analysis, has two main functions: data summarization (qualitative meta-analysis) and smoothing o. pattern recognition (quantitative meta-analysis). As well, critical reviews and syntheses with the mean and 90-percent confidence intervals for the likelihood were used to evaluate empirical evidence and significant outcomes of the BPH treatment literatures (106 articles). For this task, the Methodologic Panel for BPH Guidelines was composed of multidisciplinary experts in the field. The results of the study were summarized as follows: For all that watchful waiting is an appropriate treatment strategy for the majority of patients with prostatism, we couldn't find the Korean literatures which carried this article. The literatures on alpha-1-adrenergic receptor blockers provide no evidence to suggest that any one alpha blocker is more effective than another. The finasteride reduces the size of the prostate, on average, and leads to a small yet perceptible reduction in sysptoms. Of all treatment options, prostate surgery with transurethral resection of the prostate (TURP), transurethral incision of the prostate (TUIP), and so on, offers the best chance for symptom improvement. However, surgery also has the highest rates of significant complications. Therefore, surgery need not always be a treatment of last resort. Balloon dilation of the prostatic urethra is clearly less effective than surgery in relieving symptoms, but it is associated with fewer complications. Emerging technologies for treating BPH include lasers, coils, stents, thermal therapy and hyperthermia. Established technologies will also be reanalyzed as results of new trials are reported. Although this study has some limitations due to lacking for good quality literatures, ' it provides a cornerstone for our medical research. It represents the most current scientific knowledge regarding the clinical epidemiology including treatment of BPH. It will be revised and updated as needed.