• Economic and Environmental Geology
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• v.52 no.5
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• pp.395-407
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• 2019

The duplex system has been considered as an important slip-transfer mechanism to evaluate the evolution of orogenic belts. Duplexes are generally found in the hinterland portion of fold-thrust belts and accommodate large amounts of total shortening. Thus, understanding its geometric and kinematic evolution can give information to evaluate the evolution of the entire orogenic belt. Duplexes are recognized as closed-loop thrust traces on map view, indicating higher connectivity than imbricate fans. As originally defined, a duplex is an array of thrust horses which are surrounded by thrust faults including the floor and roof thrusts, and imbricate faults between them. Duplexes can accommodate regional layer-parallel shortening and transfer slip from a floor thrust to a roof thrust. However, an imbricate fault is not the only mean for layer-parallel shortening (LPS) and displacement transfer within duplexes. LPS cleavages and detachment folds can also play the same role. From this aspect, a duplex can be divided into three types; 1) fault duplex, 2) cleavage duplex and 3) fold duplex. Fault duplex can further be subdivided into the Boyer-type duplex, which was firstly designed duplex system in the 1980s that widely applied most of the major fold-thrust belts in the world, and connecting splay duplex, which has different time order in the emplacement of horses from those of the Boyer-type. On the contrary, the cleavage and fold duplexes are newly defined types based on some selected examples. In the Korean Peninsula, the Yeongwol area, the western part of the Taebaeksan Zone of the Okcheon Belt, gives an excellent natural laboratory to study the structural geometry and kinematics of the closed-loops by thrust fault traces in terms of a duplex system. In the previous study, the Yeongwol thrust system was interpreted by alternative duplex models; a Boyer-type hinterland-dipping duplex vs. a combination of major imbricate thrusts and their connecting splays. Although the high angled beds and thrusts as well as different stratigraphic packages within the horses of the Yeongwol duplex system may prefer the later complicate model, currently, we cannot choose one simple answer between the models because of the lack of direct field evidence and time information. Therefore, further researches on the structural field investigations and geochronological analyses in the Yeongwol and adjacent areas should be carried out to test the possibility of applying the fold and cleavage duplex models to the Yeongwol thrust system, and it will eventually provide clues to solve the enigma of formation and its evolution of the Okcheon Belt.

• Hwankyungkyoyuk
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• v.18 no.3 s.28
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• pp.59-74
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• 2005

We can't deny Korean EE has basically developed on the basis of Environmental Possibilism (Environmental management or Reformism) in lots of aspects. I would show three representative proofs here, the first, the philosophy of Korean EE has been mainly focused on dichotomy of human-techno centrism and eco-centrism with no considering other alternative environmentalism since 4th Formal Curriculum, 1981. The second, simultaneously, the concept of EE has not distinguished from it of Science education. (Furthermore, unfortunately some says EE has been a part of Science education, although there should be many differences on its contextual aspect.) And the third one is that the limit of possibilism which market economists have worried, has scarcely mentioned in various kinds of EE-related teaching materials. Possibilism is basically likely to be accompanied by science and economics-oriented approach, and in this aspect this dichotomy, human-techno centrism and eco-centrism, has come from perspectives of Economical development process and over-addicted belief to Science. So it is enough to say that Korean EE has basically developed with biased to Environmental possibilism, in other words, biased to preference to it. And I'll critically focus on these two axes of possibilism, Science and Economics and its dichotomy. Of course, we should accept there are so many same parts in its contents between EE and Science, but we should know its contextual differences for triangular position of environmentalism suitable to EE and also overcome science-dependant approach to EE. Although science-dependant approach to EE and dichotomy could provide some tools for clearing up the causes of environmental problem, especially always it has insisted fundamental causes of environmental problem originated in human faults and over-use of eco-source or over-economic development, but now it is old-fashioned discourse, furthermore it come to have unavoidable limits in the debates of problem-solving mechanism to environmental problems. The paramount important thing is to supply the ways or thoughtful mechanism for solving or coordinating the Environmental problems, not just searching for cause of it. But scientific approach and its dichotomy based on possibilism have continuously born cause & effect in EE-related discourse. So there are so much needs to transfer from continuous bearing of cause & effect to constructive alternatives at least in environmentalism of EE. Traditionally, dichotomical division in EE Environmentalism, human-techno centrism and eco-centrism, couldn't have Provided any answers to our real society, it just gives us only cause & effects of Environmental problems. And also we can't find the description on the limits of capitalism market approach to Environmental problems especially in Korean EE text books, other teaching materials and its teaching-learning process, although market approach economist has been proved its fault beyond its functional merits as Environmental management tools. So we should introduce other alternative Environmental philosophy instead of Possibilism such as eco-socialism insisted by Schmacher M. and Boochin etc, or marxist-environmentalism for relative and comparative views to market-thought such as commodification. In this aspect we need to accept Oriental philosophy based on moderation(中庸) as new another alternatives with the reflection that we have recognized monism as representative Oriental philosophical environmentalism. Fundamentally monism has done its role with providing relative concepts to Dichotomy Enlightenment, but we can't say it has been core concept for understanding of oriental environmentalism, and we can't distinguish monism from oriental philosophy itself, just because oriental thought itself was basically monism. So conceptual difference should be recognized between EE and Science education in teaching-learning process on the basis of life-philosophy(Philosophie des Lebens) from epistemology. For this transformation, we should introduce existentialism in Science education, in other words, only existential Science education based on phenomenology or interpretivism can be EE. And simultaneously we need some ways for overcoming of scientific foundationalism which has been tradition making science not stand on existentialism, formulating and featuring of almost all of natural things and its phenomenon from after enlightenment in western world, but it has malfunctioned in fixing conception of science just into essentialism itself. And we also introduce integrated approach to science and society for EE like STS. Those are ways for overcoming of Environmental possibilism in EE.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.463-466
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• 2017

The purpose of this paper is to develop a module capable of all-directional driving different from conventional wheeled robots, and to solve the problems of the conventional mobile robot with side driving performance degradation, It is possible to overcome the disadvantages such as an increase in the time required for the unnecessary driving. The all - direction spherical wheel drive module for driving a ball - balancing robot is required to develop a power transfer mechanism and a driving algorithm for driving the robot in all directions using three rotor casters. 3DoF (Axis) A driver with built-in forward motion algorithm is embedded in the module and a driving motor module with 3DoF (axis) for driving direction and speed is installed. The movement mechanism depends on the sum of the rotation vectors of the respective driving wheels. It is possible to create various movement directions depending on the rotation and the vector sum of two or three drive wheels. It is possible to move in different directions according to the rotation vector field of each driving wheel. When a more innovative all-round spherical wheel drive module for forward movement is developed, it can be used in the driving part of the mobile robot to improve the performance of the robot more technically, and through the forward-direction robot platform with the drive module Conventional wheeled robots can overcome the disadvantage that the continuous straightening performance is lowered due to resistance to various environments. Therefore, it is necessary to use a full-direction driving function as well as a cleaning robot and a mobile robot applicable in the Americas and Europe It will be an essential technology for guide robots, boarding robots, mobile means, etc., and will contribute to the expansion of the intelligent service robot market and future automobile market.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.115-130
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• 2013

The sectional methods of current design codes have been broadly used for the design of various kinds of reinforced concrete pile caps. Lately, the strut-tie model approach of current design codes also became one of the attracting methods for pile caps. However, since the sectional methods and the strut-tie model approach of current design codes have been established by considering the behaviors of structural concrete without D-regions and two-dimensional concrete structures with D-regions, respectively, it is inappropriate to apply the methods to the pile caps dominated by 3-dimensional structural behavior with disturbed stress regions. In this study, the refined 3-dimensional strut-tie models, which consider the strength characteristics of 3-dimensional concrete struts and nodal zones and the load-carrying capacity of concrete ties in tension regions, are proposed for the rational analysis and design of pile caps. To examine the validity of the proposed models and to verify the necessity of appropriate constituent elements for describing 3-dimensional structural behavior and load-transfer mechanism of pile caps, the ultimate strength of 78 reinforced concrete pile caps tested to failure was examined by the proposed models along with the sectional and strut-tie model methods of current design codes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.159-167
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• 2006

IEEE 802.11i standard specifies full authentication and preauthentication for secure handoff in 802.11 wireless LAN (WLAN). However, the full authentication is too slow to provide seamless services for handoff users, and preauthentication may fail in highly populated WLAN where it is highly probable that the cache entry of a preauthenticated user is evicted by other users before handoff. In this paper, we propose a fast and secure handoff scheme by reducing authentication and key management delay in the handoff process. When a user handoffs, security context established between the user and the previous access point (AP) is forwarded from the previous AP to the current AP, and the session key is reused before the handoff session terminates. The freshness of session key is maintained by regenerating session keys after handoff session is terminated. The proposed scheme can achieve considerable reduction in handoff delay with providing the same security level as 802.1X authentication by letting an AP authenticate a handoff user before making an robust security network association (RSNA) with it.

• Journal of the Korean Chemical Society
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• v.46 no.3
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• pp.179-186
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• 2002

A molecular orbital analysis based on the extended Huckel calculations has been carried out to study the OH bond activation of water on the $TiO_2$(110) surface. $H_2O$ binds with its axis perpendicular to the surfac on top of the five-coordinate $Ti^{4+}$ atom via its $3a_1$ orbital. In this bonding situation, the two-coordinated bridging $O^{2-}$ atom ($O_b$, basic site) on $TiO_2$(110) is too distant from an H atom of water to form hydrogen-bondig interactions with water that facilitate O-H bond cleavage. It has been elucidated that the O-H bond is appreciably weakened when the water molecule is tilted to give a hydrogen bond with the $O_b$ atom. This mechanism includes mutual transfer of electron density from the $3a_1$ orbital of the water molecule to the $Ti^{4+} 3d_{z2}$ orbital and from the $O_b$ P orbitals to the $2b_1$ of the adsorbed water molecule This should result in lengthening of the O-H bond in the surface complex and the subsequent dissociation into the fragments OH and H.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.211-224
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• 2008

Characteristics of the esterification reaction between free fatty acid in rice bran oil and methanol was investigated in the presence of catalysts, such as PTS(p-toluene sulfonic acid), Amberlyst 15 dry and SCX(silica gel based strong cation exchange resin). While reaction temperature was kept constant at $65^{\circ}C$, initial feed content of free fatty acid was varied from 100% to 1% by addition of pure free fatty acid which was previously made from rice bran oil. Also, the effect of mole ratio of methanol to fatty acid on the final conversion was examined. When esterification of pure free fatty acid was catalyzed by several acids, final conversions were increased in order of Amberlyst 15 dry, SCX and PTS. Using PTS catalyst, initially the reaction proceeded in homogeneous 2nd oder reaction mechanism. However, phase of reaction mixture changed from homogeneous to heterogeneous along the reaction time and then reaction rate was retarded by mass transfer resistance of methanol. Final conversion of free fatty acid in reaction mixture was depended on initial feed content of free fatty acid, and had maximum value at 30% of initial feed free fatty acid content for all kinds of catalysts used. And the final conversion was increased with mole ratio of methanol by the improvement of reaction rate. When initial feed free fatty acid content below 10% and the reaction was catalyzed by PTS, concentration of free fatty acid in reaction mixture was increased in the middle of reaction time by hydrolysis of triglyceride in reaction mixture. Also, if silica gel was added into the reaction mixture which had initial feed free fatty acid content below 50%, final conversion was increased by the adsorption of moisture produced. The SCX catalyst made the esterification reaction of free fatty acid to progress like in case of PTS catalyst. However, when initial feed free fatty acid content below 10%, concentration of free fatty acid in. reaction mixture was decreased monotonically and not increased in the middle of reaction time on the contrary to the case of PTS. Thus, SCX catalyst accomplished more high value of final conversion than PTS catalyst for the initial feed fatty acid content range from 50% to 5% In case of initial feed free fatty acid content of 1% and mole ratio of methanol was 2, concentration of free fatty acid in reaction mixture increased over the initial feed free fatty acid content for all kind of catalysts used. Although SCX catalyst was added into reaction mixture which had 1% of initial feed fatty acid content, final conversion was hardly raised by mole ratio of methanol.

• Journal of Korean Society of Steel Construction
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• v.26 no.6
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• pp.523-535
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• 2014

According to the capacity design concept underlying current steel seimsic provisions, the braces in concentrically braced frames should dissipate seismic energy through cyclic tension yielding and compression buckling. On the other hand, the beams and the columns in the braced bay should remain elastic for gravity load actions and additional column axial forces resulting from the brace buckling and yielding. However, due to the difficulty in accumulating the yielding and buckling-induced column forces from different stories, empirical and often conservative approaches have been used in design practice. Recently a totally different approach was proposed by Cho, Lee, and Kim (2011) for the prediction of column axial forces in inverted V-braced frames by explicitly considering brace buckling. The idea proposed in their study is extended to X-braced seismic frames which have structural member configurations and load transfer mechanism different from those of inverted V-braced frames. Especially, a more efficient rule is proposed in combining multi-mode effects on the column axial forces by using the modal-mass based weighting factor. The four methods proposed in this study are evaluated based on extensive inelastic dynamic analysis results.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.19-29
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• 1996

The neurological manifestations of AIDS include dementia, encountered even in the absence of opportunistic superinfection or malignancy. The AIDS Dementia Complex appears to be associated with several neuropathological abnormalities, including astrogliosis and neuronal injury or loss. How can HIV-1 result in neuronal damage if neurons themselves are only rarely, if ever, infected by the vitus\ulcorner In vitro experiments from several different laboratiories have lent support to the existence of HIV- and immune-related toxins. In one recently defined pathway to neuronal injury, HIV-infected macrophages/microglia as well as macrophages activated by HIV-1 envelope protein gp120 appear to secrete excitants/neurotoxins. These substances may include arachidonic acid, platelet-activating factor, free radicals (NO - and O$_2$), glutamate, quinolinate, cysteine, cytokines (TNF-${\alpha}$, IL1-B, IL-6), and as yet unidentified factors emanating from stimulated macrophages and possibly reactive astrocytes. A final common pathway for newonal suscepubility appears to be operative, similar to that observed in stroke, trauma, epilepsy, and several neurodegenerative diseases, including Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This mechanism involves excessive activation of N-methyl-D-aspartate (NMDA) receptor-operated channels, with resultant excessive influx of Ca$\^$2+/ leading to neuronal damage, and thus offers hope for future pharmacological intervention. This chapter reviews two clinically-tolerated NMDA antagonists, memantine and nitroglycerin; (ⅰ) Memantine is an open-channel blocker of the NMDA-associated ion channel and a close congener of the anti-viral and anti-parkinsonian drug amantadine. Memantine blocks the effects of escalating levels of excitotoxins to a greater degree than lower (piysiological) levels of these excitatory amino acids, thus sparing to some extent normal neuronal function. (ⅱ) Niuoglycerin acts at a redox modulatory site of the NMDA receptor/complex to downregulate its activity. The neuroprotective action of nitroglycerin at this site is mediated by n chemical species related to nitric oxide, but in a higher oxidation state, resulting in transfer of an NO group to a critical cysteine on the NMDA receptor. Because of the clinical safety of these drugs, they have the potential for trials in humans. As the structural basis for redox modulation is further elucidated, it may become possible to design even better redox reactive reagents of chinical value. To this end, redox modulatory sites of NMDA receptors have begun to be characterized at a molecular level using site-directed mutagenesis of recombinant subunits (NMDAR1, NMDAR2A-D). Two types of redox modulation can be distinguished. The first type gives rise to a persistent change in the functional activity of the receptor, and we have identified two cysteine residues on the NMDARI subunit (#744 and #798) that are responsible for this action. A second site, presumably also a cysteine(s) because <1 mM N-ethylmaleimide can block its effect in native neurons, underlies the other, more transient redox action. It appears to be at this, as yet unidentified, site on the NMDA receptor that the NO group acts, at least in recombinant receptors.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.555-562
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• 2016

The objective of the present study is to evaluate the shear transfer capacity of transverse reinforcement at the concrete interfaces with smooth construction joint. The transverse reinforcing bars were classified into two groups: V-type for the arrangement perpendicular to the interface and X-type for inclined-crossing arrangement. The transverse reinforcement ratio at the interface varied from 0.0045 to 0.0135 for V-type and 0.0064 to 0.0045 for X-type. The mechanism analysis proposed for monolithic concrete interface, derived based on the upper-bound theorem of concrete plasticity, was modified to evaluate the shear friction capacity of concrete interfaces with smooth construction joint. Test results showed that the specimens with X-type reinforcement had lower amount of relative slippage at the interface and higher shear friction capacity than the companion specimens with V-type reinforcement. This observation was independent of the unit weight of concrete. The mean and standard deviation of the ratios between the experimental shear friction strength of smooth construction joints and predictions obtained from the proposed model are 1.07 and 0.14, respectively.