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동형 모더나이트 상에서 일산화탄소 산화반응에 대한 속도론
정명수,이창용,최고열,하백현 漢陽大學校 環境科學硏究所 1989 環境科學論文集 Vol.10 No.-
모더나이트에 동을 이온교환 및 담지시킨 후 환원·산화 처리를 하여 동의 상태를 변화시킨 촉매에 대해 일산화탄소 산화반응의 속도론적인 고찰을 행하였다. 이온교환 촉매나 담지촉매 모두 동의 상태와는 관계없이 일산화탄소에 관한 반응차수는 1차이고 산소에 관한 반응차수는 0차였다. 이온교환 촉매의 경우는 수소로 환원시켜 동이 금속상태로 존재할때와 이를 재산화시켜 산화동 상태로 존재할때는 활성화에너지가 각각 16.4 및 20.3으로 비교적 큰 값을 나타냈으나 동의 담지촉매의 경우는 동이 금속일 때나 산화물 상태 모두 12∼13kcal/mole로 비슷한 값을 나타냈으며 이온교환 촉매보다 상당히 감소함을 알 수 있었다. 이와 같은 결과는 이온교환 촉매의 경우는 동이 제올라이트내부에 대부분 존재하는 반면, 담지촉매의 경우는 제올라이트 결정 표면에 존재하기 때문에 활성을 증가시키는 것으로 생각된다. Kinetics of oxidation of carbon monoxide over copper mordenite was carried out at the temperature range between 373K-443K in the micro-catalytic reactor. The experimental results indicated that the reaction order, with respect to carbon monoxide and oxygen was first and zero order respectively, regardless of the valence states such as copper metal, copper ion and copper oxide on the mordenite. The activation energy for metal-copper mordenite which is obtained by the ion-exchange revealed 20kcal/mol. But if this was reoxidized under the oxygen it decreased to 16.6kcal/mol. The activation energy of metal-copper mordenite which was obtained by impregnation and its reoxidized one under the oxygen were 12.2kcal/mol and 13.3kcal/mol respectively.
고분자 전해질형 연료전지에서 Hot Pressing 조건의 영향
이태희,이승재,조원일,노용우,고영태,최경환 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.1
고분자 전해질형 연료전지에서 고분자막/전극 어셈블리를 hot pressing 조건을 달리하여 제조하고 그 성능을 반응면적 5㎠인 단위전지에서 측정하였다. 전지의 성능은 고분자막과 전극간의 접합이 가능한 온도 범위에서 hot pressing온도가 낮을수록, hat Pressing 압력이 높을수록 향상되었다. 즉, 고분자 전해질형 연료전지의 성능은 고분자 전해질 내의 수분 함량 증가, 고분자막/전극간 접촉저항 감소 및 얇은 고분자막을 사용한 전해질의 이온저항 감소 등으로 향상시킬 수 있었다. For a proton exchange membrane fuel cell, membrane and electrode assemblies were fabricated by different hot pressing conditions and those performances were observed in a unit cell having 5 ㎠ active electrode area. The cell performance increased with lower hot pressing temperature in the range of temperature having intimate contact between membrane and electrodes and with higher hot pressing pressure. Namely, the performance of proton exchange membrane fuel cell could be raised with higher water content in the membrane, with lower contact resistance between membrane and electrodes and with lower ion resistance of the electrolyte using thinner membrane.
Agora and Its Possibilities in James Joyce’s “Wandering Rocks”
Kho, Younghee 미래영어영문학회 2021 영어영문학 Vol.26 No.1
Reviving and representing the concept of agora, a central space for the politics, economy, and religion of ancient Greek city-states, this paper claims that Joyce in Dubliners and Ulysses evaluates the limitations and possibilities of Ireland as an emerging nation through the citizens’ interactions in agora. Focusing on this public space’s role for communication, the paper pays attention to the kinds and characters of communication especially in “Eveline” and “Wandering Rocks.” In the former story, Eveline is occupied in her uncommunicable concern of whether or not she has to leave Ireland, yet her agoraphobia ultimately ends her communication with others, especially with Frank who she regards as a possible savior from her stifling situation. The citizens in “Wandering Rocks” do not show such physical symptoms of agoraphobia as Eveline; however, their consciousness and communication still expose what obstructs themselves from intellectual development. The pretentious and uncharitable attitude of Dubliners, perhaps except for foreign Bloom and female Molly, marks their communication everywhere and develops a false community in this episode. Molly and Bloom, in contrast, open up possibilities for building an ideal community through the act of charity, which is particularly emphasized in this episode.
An incremental learning method for spoof fingerprint detection
Kho, Jun Beom,Lee, Wonjune,Choi, Heeseung,Kim, Jaihie Elsevier 2019 expert systems with applications Vol.116 No.-
<P><B>Abstract</B></P> <P>Spoof fingerprint detectors based on static features are built by learning a set of live and fake fingerprint images. These learning-based spoof detectors cannot accurately classify new or untrained types of fakes. To handle this problem, the existing spoof detector should be incrementally trained on the new types of fakes. This paper proposes a new spoof detection framework to learn new types of fakes incrementally without retraining the existing spoof detector repeatedly. The proposed model discriminates the newly learned fakes without serious loss of performance for the previously learned fakes and at the same time provides promising detection results for the various types of fakes. The proposed spoof detector integrates multiple “experts,” each of which shares the same structure but is separately trained for a different set of fake fingerprints. To detect a new type of fake fingerprint, a new expert exclusively trained on the new fake type is integrated into the spoof detector. Each expert consists of multiple support vector machines (SVMs) applied by an incremental learning algorithm (Learn++.NC), where each SVM adopts one of three texture features for spoof detection. Experimental results show the superiority of the proposed method compared with other methods in various scenarios.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new spoof fingerprint detection framework to learn new fakes incrementally. </LI> <LI> An expert-construction method is proposed, based on boosting and SVMs. </LI> <LI> A dynamic weight-update rule is proposed to combine multiple experts. </LI> <LI> The proposed method provides high incremental learning ability. </LI> </UL> </P>
Cancelable fingerprint template design with randomized non-negative least squares
Kho, Jun Beom,Kim, Jaihie,Kim, Ig-Jae,Teoh, Andrew B.J. Elsevier 2019 Pattern recognition Vol.91 No.-
<P><B>Abstract</B></P> <P>Although biometrics is considered more competent than password-based or token-based approach in identity management, biometric templates are vulnerable to adversary attacks that may lead to irreversible identity loss. One of the promising remedies for biometric template protection is cancelable biometrics. In this paper, a novel binary cancelable fingerprint template design based on Partial Local Structure (PLS) descriptor and Permutated Randomized Non-Negative Least Square (PR-NNLS) is proposed. The PLS descriptor is an alignment-free minutia descriptor, which is conceived to be coupled with the PR-NNLS to derive a binary protected fingerprint template that satisfies non-invertibility, unlinkability, cancelability and performance criteria. The PR-NNLS formulation is unique in such a way that the noninvertible transformation is applied to the PLS descriptor dictionary instead of applying it to the minutiae descriptor, which often invites performance deterioration. The evaluations have been carried out with five subsets from FVC 2002 and 2004 databases where the proposed method is attested to fulfill the aforementioned four template protection criteria. We also analyze four privacy and security attacks targeted to cancelable biometrics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel alignment-free minutiae descriptor that based on Partial Local Structure (PLS) is proposed, which is beneficial to generate discriminative and compact binary cancelable fingerprint template. </LI> <LI> The non-invertible transformation of the PLS descriptor is formulated as a problem of solving randomized Non-Negative Least Square (R-NNLS) optimization problem, which is unique in a way to get rid of the performance deterioration issue when applying the non-invertible transformation directly to the minutiae descriptor for the fingerprint template protection. </LI> <LI> The revocability and the unlinkability traits of the proposed method are enabled by introducing a permutation mechanism to the R-NNLS. </LI> <LI> The proposed method is rigorously evaluated with five benchmark datasets, and four security and privacy analyses are also carried out. </LI> </UL> </P>
고승영,고종섭,전종수 明知大學校 産業技術硏究所 1999 産業技術硏究所論文集 Vol.18 No.-
This study is to develop for the headway scheduling of bus and to deal with the efficient management of bus, Traffic problems of a large city are major social problems in many developed countries as well as Korea. They have made efforts to solve problems by developing and introducing ITS(ITS: Intelligent Transport System) technology. APTS(APTS: Advanced Public Transportation Systems) is a subsystem of ITS. It is to present users travel informations and to increase the efficiency by improving the operation and management of a vehicle. This study, that can be a part of APTS, makes use o the skill of AVL(AVL: Automatic Vehicle Location). If, by real time, we could know the condition of vehicle traveling condition and we could manage the vehicle scheduling, it can give constant level of service to users. And also, this study presented the way of the vehicle management more efficiently by developing the dispatch headway scheduling and real time scheduling model.
Effects of Protocatechuic Acid (PCA) on Global Cerebral Ischemia-Induced Hippocampal Neuronal Death
Kho, A Ra,Choi, Bo Young,Lee, Song Hee,Hong, Dae Ki,Lee, Sang Hwon,Jeong, Jeong Hyun,Park, Kyoung-Ha,Song, Hong Ki,Choi, Hui Chul,Suh, Sang Won MDPI 2018 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.19 No.5
<P>Global cerebral ischemia (GCI) is one of the main causes of hippocampal neuronal death. Ischemic damage can be rescued by early blood reperfusion. However, under some circumstances reperfusion itself can trigger a cell death process that is initiated by the reintroduction of blood, followed by the production of superoxide, a blood–brain barrier (BBB) disruption and microglial activation. Protocatechuic acid (PCA) is a major metabolite of the antioxidant polyphenols, which have been discovered in green tea. PCA has been shown to have antioxidant effects on healthy cells and anti-proliferative effects on tumor cells. To test whether PCA can prevent ischemia-induced hippocampal neuronal death, rats were injected with PCA (30 mg/kg/day) per oral (p.o) for one week after global ischemia. To evaluate degenerating neurons, oxidative stress, microglial activation and BBB disruption, we performed Fluoro-Jade B (FJB), 4-hydroxynonenal (4HNE), CD11b, GFAP and IgG staining. In the present study, we found that PCA significantly decreased degenerating neuronal cell death, oxidative stress, microglial activation, astrocyte activation and BBB disruption compared with the vehicle-treated group after ischemia. In addition, an ischemia-induced reduction in glutathione (GSH) concentration in hippocampal neurons was recovered by PCA administration. Therefore, the administration of PCA may be further investigated as a promising tool for decreasing hippocampal neuronal death after global cerebral ischemia.</P>