• ETRI Journal
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• v.33 no.3
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• pp.344-354
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• 2011

In this paper, a model is introduced named double relation chains (DRC) based on ordered sets. It is proved that using DRC and special relationships among the members of an alphabet, vectors of this alphabet can be stored and searched in a tree. This idea is general; however, one special application of DRC is the longest prefix matching (LPM) problem in an IP network. Applying the idea of DRC to the LPM problem makes the prefixes comparable like numbers using a pair of w-bit vectors to store at least one and at most w prefixes, where w is the IP address length. This leads to good compression performance. Based on this, two recently introduced structures called coded prefix trees and scalar prefix trees are shown to be specific applications of DRC. They are implementable on balanced trees which cause the node access complexity for prefix search and update procedures to be O(log n) where n is the number of prefixes. As another advantage, the number of node accesses for these procedures does not depend on w. Additionally, they need fewer number of node accesses compared to recent range-based solutions. These structures are applicable on both IPv4 and IPv6, and can be implemented in software or hardware.

• Steel and Composite Structures
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• v.20 no.2
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• pp.357-378
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• 2016

The progressive collapse phenomenon in structures has been interested by civil engineers and the building standards organizations. This is particularly true for the tall and special buildings ever since local collapse of the Ronan Point tower in UK in 1968. When initial or secondary defects of main load carrying elements, overloads or unpredicted loads occur in the structure, a local collapse may be arise that could be distributed through entire structure and cause global collapse. One is not able to prevent the reason of failure as well as the prevention of propagation of the collapse. Also, one is not able to predict the start point of collapse. Therefore we should generalize design guides to whole or the part of structure based on the risk analysis and use of load carrying elements removal scenario. There are some new guides and criteria for elements and connections to be designed to resist progressive collapse. In this paper, codes and recommendations by various researchers are presented, classified and compared for steel structures. Two current design methods are described in this paper and some retrofitting methods are summarized. Finally a steel building with special moment resistant frame is analyzed as a case study based on two standards guidelines. This includes consideration of codes recommendations. It is shown that progressive collapse potential of the building depends on the removal scenario selection and type of analysis. Different results are obtained based on two guidelines.

• Journal of Dental Anesthesia and Pain Medicine
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• v.21 no.5
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• pp.431-440
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• 2021

Background: Neurovascular compression (NVC) is a well-known cause of trigeminal neuralgia (TN). However, patients with idiopathic TN (ITN) do not have evidence of NVC on magnetic resonance imaging (MRI), and other patients may remain asymptomatic despite evidence of NVC on MRI. This suggests that there may be additional risk factors for TN development other than NVC. Although epidemiological factors, such as age and sex differences, are useful for understanding the pathophysiology of TN, detailed statistics for each TN subtype are currently unavailable. Therefore, this study aimed to classify patients with TN into the following groups based on data extracted from past medical records: classical TN (CTN), secondary TN, and ITN. Methods: The characteristics of the groups and their differences were explored. Results: CTN was more common in women than in men, as previously reported, whereas ITN was more common in men than in women. The ratio of pain sites located on the right side of the face was high in all groups. Patients with CTN were also prone to NVC on the asymptomatic side. Conclusion: By investigating TN subtype, it may be possible to elucidate the pathophysiology of TN. This would greatly improve treatment outcomes.

• Geomechanics and Engineering
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• v.33 no.1
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• pp.91-99
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• 2023

To test the effect of various pile tip shape series of model scale loading tests were carried out on test piles with special pile tips. Special pile tips were made using the 3D printer and were attached to the bottom end of the test pile for loading tests. The pile tips were made to have 30°, 45°, 60° inclined tips, as well as a rounded tip. The main objective of the test was to observe the effect of various pile tip shapes on settlement and penetrability of the pile. Moreover, a numerical model simulating the pile loading test carried out in this study was established and verified based on the loading test results. From this, the stress concentration around the pile tip was investigated. This will allow us to analyze the decrease of stress concentration around the pile tip which is the main cause of the pile tip damage during pile installation. However, modifying the pile tip shape will eventually increase the settlement of the pile. By estimating the degree of increase in pile settlement, the viability and the efficiency of the pile shape modification was judged. In addition, case studies on the effect of different pile tip shape and ground conditions on pile settlement and stress dispersion was conducted.

• Journal of Korean Society of Steel Construction
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• v.21 no.1
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• pp.63-70
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• 2009

Failure modes result in fracture or tearing, which may cause deterioration of resistance and reduction of inelastic deformation capacity. The potential failure modes for Special Concentrically Braced Frames (SCBFs) include fracture or tearing of the brace, net section fracture of the brace or gusset plate, fracture of the gusset plate welds, shear fracture of the bolts, block shear, excessive bolt bearing deformation, and buckling of the gusset plate. HSS tubular braces are commonly used in SCBFs, and net section fracture of the tubular brace may also occur through the brace net section at the end of the slot cut into the tube to slip over the gusset plate. This failure mode is categorized as a tension failure mode, and may cause dramatic loss of resistance and brittle behavior. Net section reinforcement is required according to AISC design specifications (AISC 2001). In this paper, the need to reinforce the net section area was discussed. Initially, the results of the net section fracture tests done by the University of California in Berkeley were presented with the modeling of these tests using FE models. To investigate the possibility of net section fracture in an actual frame, the slot end hole model was adapted to the frame FE model, and alternate near-fault histories were applied with tension-dominated cycles, since previous analyses showed that loading history was the most critical factor in net section fracture. The need for this reinforcement (cover plate) and the tension-dominated near-fault history were investigated.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.460-466
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• 2017

The common petroleum can make precipitation such as a wax in a polar region due to severely cold weather condition, which can cause problems to fuel supply system. The petroleum product used in the polar region has thus been manufactured and sold suitable for the cold environment. However it is difficult to supply such petroleum products on time since these were mainly supplied abroad. In this article, the original fuel properties were first analyzed in order to find alternative fuel products for polar region. Jet fuel which is excellent cold characteristics was chosen and the fuel properties was tested by adding a constant concentration of lubricant additives to the jet fuel. As a result, the lubricant additive R621 showed the best lubricity, and adding 1000 mg/L of R621 content to the jet fuel was sufficient to enhance the lubricity. We envision that the jet fuel added 1000 mg/L of R621A can be suitable for alternative special antarctic blend diesel (SAB) in an severe polar environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.4 no.1
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• pp.8-24
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• 1979

Including the Qualfication of Staffer required for Commuinication, the National Law of Professional qualification is a basic law for supply with manpower of high growth industry, and it is aiming at perfect the national Policy Concerned improvement for education and training of staff, carrying out of state examination for qualification and getting an occupation or application for special qualification. This law has established a management committee for qualification system in The Ministry of Science and Technique ROK, and authorized competence Minister according to kind of special qualification aiming at getting employment, practical use and courteous treatment in society and economy for national qualification, and also regulated their each official duty. A qualification of staffer required for communication is an administrative measure giving as occupational certificate after some examination for knowledge, technique and faculty in vocational ability to adapt to intrinsic of telecommunication. This certificate has the cause of an attribution of over the sphere of telecommunication, and so it has been originated in international situation, and then some of them is forced by international law, otherwise it be in common use between the nations. The Characteristic and orthodox of communication certificate has been succeded continually in company with development of telecommunication and the appliable field of them is specified, but the sovereign power of nation is approved by ITU that she can extent the applicable position for communication certificate and coordinate the utility of qualification for telecommunication value. Korean telecommunication law excepted the application of communication certificate in public communication field. It is unreasonable and even disobeyed against the theory of communication science and intrinsic of telecommuncation. Therefore it should be corrected immediately and then communication certificate have to accept in the public communication field at all, if so, the application field of communication certificate can have more than useful extenxion such as administration measure should be achieved by the management committee for qualification system in Ministry of Science and Technique and competemce Minister appointed according to special kind of certificate and the administration have to manage by the method and proccess caused by communication science or cooperative system between administration, industry, education and science. And, then, every acquisitor of qualification also has to try to perfect his vocational duty sincerely and to promote each self-realization.

• The Journal of Korean Academic Society of Nursing Education
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• v.4 no.1
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• pp.15-27
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• 1998

In order to help students through their initial clinical experience, faculty must understand more fully the moaning of this experience for nursing students. This study was performed to understand and to explain what is the essential structure of nursing students' initial clinical experience. A grounded theory approach was conducted to explore the actual experience of nursing students' first clinical experience. Each of the nursing students' descriptions about their initial clinical experience was analyzed using Strauss & Corbin's method. The results of the study were as follows : From the 172 written descriptions and 7 in-depth individual interviews, 128 concepts were extracted. After identifying the concepts' formulated meaning, they were organized into 29 subcategories and the following 12 categories . burden, encountering difficulties, self-discovery, grasping actuality, acquirement of nurse's nature, special character of experience, special character of relationship, external effect, problem oriented coping, emotional oriented coping, affection for nursing, skeptical view of nursing. Five hypotheses were derived from the analysis. 1) Burden is an obstacle to grasp nursing actuality. 2) Special character of experience and external effect have an effect on grasping nursing actuality, 3) Encouragement, a part of external effects, will increase nursing student's affection for nursing. 4) Affection for nursing through first clinical experience facilitates positive nursing view and scholarly zest. 5) Disappointment with the difference be tween theory and reality will cause the student to take a skeptical view of nursing. It is hoped that the knowledge gained from this qualitative study will enable faculty to enter more fully Into the world of nursing students as they embark on their initial clinical experience.

• Journal of Korean Society of Disaster and Security
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• v.5 no.2
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• pp.61-70
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• 2012

The range of special management target facilities is seperated by the building sector and the field of civil engineering. In the present study, the risk analysis was performed, related to fire occurred for the last five years, in the field of residential and non-residential facilities in buildings. Most of fire incidents occurred in residential and non-residential facilities was the cause of the electrical, and the resulting casualties were also very high. Therefore, based on the results, the risk evaluation index was developed, identifying the causes of fire occur and doing the fire vulnerability analysis for each facility. The result of this study can be utilized safety management to these facilities for the future, especially, inducing a more specialized and intensive safety management.

• Clean Technology
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• v.14 no.3
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• pp.193-203
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• 2008

A surfactant is used to assist the effect of cleaning, dispersibility and adhesion during leather manufacturing process. Existing surfactant for that process includes many hydrophilic groups that may cause problem such as stain, bad water resistance and poor durability, etc. It is potential problem to make high-performance property for future leather market. In this study, we have synthesized the fluorinated surfactant of which property decreases surface tension, increases dispersion, cleaning effect and the better chrome absorption by the high bond energy of C-F to complement weakness that the present alkyl derivative surfactants have. Using fluorinated surfactant, we can confirm that dispersion is increased, chrome absorption ratio is augmented with high osmosis and coherence, chrome content in the tanning waste water is reduced, BOD and COD contents are diminished and physical characteristics are improved.