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Failure Paths of Polymer/Roughened Metal Interfaces under Mixed-Mode Loading (혼합 하중하에서의 고분자/거친금속 계면의 파손경로)

  • Lee Ho-Young;Kim Sung-Ryong
    • Korean Journal of Materials Research
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    • v.14 no.5
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    • pp.322-327
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    • 2004
  • Copper-based leadframe sheets were oxidized in two kinds of hot alkaline solutions to form brown-oxide or black-oxide layer on the surface. The oxide coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched Brazil-nut (SBN) specimens. The SBN specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under mixed-mode (mode I + mode II) loading conditions. Fracture surfaces were analyzed by various equipment to investigate failure path. The results revealed that the failure paths were strongly dependent on the oxide type. In case of brown oxide, hackle-type failure was observed and failure path lay near the EMC/CuO interface with a little inclining to CuO at all case. On the other hand, in case of black oxide, quite different failure path was observed with respect to the distance from the tip of pre-crack and phase angle. Different failures occurred with oxide type is presumed to be due to the difference in microstructure of the oxides.

Failure Path of the Brown-oxide-coated Copper-based Leadframe/EMC Interface under Mixed-Mode Loading (혼합하중 조건하에서 갈색산화물이 입혀진 구리계 리드프레임/EMC 계면의 파손경로)

  • 이호영
    • Journal of Surface Science and Engineering
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    • v.36 no.6
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    • pp.491-499
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    • 2003
  • Copper-based leadframe sheets were oxidized in a hot alkaline solution to form brown-oxide layer on the surface and molded with epoxy molding compound (EMC). The brown-oxide-coated leadframe/EMC joints were machined to form sandwiched double-cantilever beam (SDCB) specimens and sandwiched Brazil-nut (SBN) specimens for the purpose of measuring the fracture toughness of leadframe/EMC interfaces. The SDCB and the SBN specimens were designed to measure the fracture toughness of the leadframe/EMC interfaces under nearly mode-I loading and mixed-mode (mode I + mode II) loading conditions, respectively. Fracture surfaces were analyzed by various equipment such as glancing-angle XRD, SEM, AES, EDS and AFM to elucidate failure path. Results showed that failure occurred irregularly in the SDCB specimens, and oxidation time of 2 minutes divided the types of irregular failures into two classes. The failure in the SBN specimens was quite different from that in the SDCB specimens. The failure path in the SBN specimens was not dependent on the phase angle as well as the distance from tips of pre-cracks.

Research on Cyber IPB Visualization Method based on BGP Archive Data for Cyber Situation Awareness

  • Youn, Jaepil;Oh, Haengrok;Kang, Jiwon;Shin, Dongkyoo
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.2
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    • pp.749-766
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    • 2021
  • Cyber powers around the world are conducting cyber information-gathering activities in cyberspace, a global domain within the Internet-based information environment. Accordingly, it is imperative to obtain the latest information through the cyber intelligence preparation of the battlefield (IPB) process to prepare for future cyber operations. Research utilizing the cyber battlefield visualization method for effective cyber IPB and situation awareness aims to minimize uncertainty in the cyber battlefield and enable command control and determination by commanders. This paper designed architecture by classifying cyberspace into a physical, logical network layer and cyber persona layer to visualize the cyber battlefield using BGP archive data, which is comprised of BGP connection information data of routers around the world. To implement the architecture, BGP archive data was analyzed and pre-processed, and cyberspace was implemented in the form of a Di-Graph. Information products that can be obtained through visualization were classified for each layer of the cyberspace, and a visualization method was proposed for performing cyber IPB. Through this, we analyzed actual North Korea's BGP and OSINT data to implement North Korea's cyber battlefield centered on the Internet network in the form of a prototype. In the future, we will implement a prototype architecture based on Elastic Stack.

TREE FORM CLASSIFICATION OF OWNER PAYMENT BEHAVIOUR

  • Hanh Tran;David G. Carmichael;Maria C. A. Balatbat
    • International conference on construction engineering and project management
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    • 2011.02a
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    • pp.526-533
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    • 2011
  • Contracting is said to be a high-risk business, and a common cause of business failure is related to cash management. A contractor's financial viability depends heavily on how actual payments from an owner deviate from those defined in the contract. The paper presents a method for contractors to evaluate the punctuality and fullness of owner payments based on historical behaviour. It does this by classifying owners according to their late and incomplete payment practices. A payment profile of an owner, in the form of aging claims submitted by the contractor, is used as a basis for the method's development. Regression trees are constructed based on three predictor variables, namely, the average time to payment following a claim, the total amount ending up being paid within a certain period and the level of variability in claim response times. The Tree package in the publicly available R program is used for building the trees. The analysis is particularly useful for contractors at the pre-tendering stage, when contractors predict the likely payment scenario in an upcoming project. Based on the method, the contractor can decide whether to tender or not tender, or adjust its financial preparations accordingly. The paper is a contribution in risk management applied to claim and dispute resolution practice. It is argued that by contractors having a better understanding of owner payment behaviour, fewer disputes and contractor business failures will occur.

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The relation of Creating Actor's Aura and Conscious Liminality of Acting - a conceptual understanding as a searching process for materiality - (연기의 기술적, 의식적 리미널리티(liminality)와 배우의 아우라의 상관성 - 물질성 탐색의 한 과정으로서의 개념적 이해 -)

  • Kwon, Kyoung-Hee
    • Journal of Korean Theatre Studies Association
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    • no.53
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    • pp.31-56
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    • 2014
  • If we define theatre as an infinite tower piled up by smoke, the strata of the organic composition of an actor's/actress' body-mind-spirit, may not only be complicatedly worked out, but it seems to belong to a non-scientific realm. However and at the same time, it is also true that the audience is eager to witness a certain kind of specific vitality from the actor/actress on stage. Of course the vitality is hard to be prescribed. Simply we call it a texture of energy, nuance of existence, or much simpler, an actor's/actress' 'aura'. That is, the existential nuance of the actor/actress. The nuance, which is surging from the actor's/actress' authentic presence, ultimately comes out of, not the circumstantial interpretation of the production but the power of its integration. We can find from the works of Meyerhold, Grotowsky and Barba the theatrical fact that the actor's aura can be obtained by a kind of artificiality rather than innate characteristics of existence. These directors commonly regard theatre as the actor's/actress' theatre. Respectively choosing his own specific methods of expression, they unexpectedly meet in a same spot in which actor's/actress' theatre can be realized by the rediscovery of the actor's/actress's body-form. In other words, their approaching methods to theatre look alike, at least in that abandoning reserving any natural, unconscious, economic body-form of an actor/actress, they rather try to discover a certain kind of 'technical' body-form. The form which is totally non/un-conscious, unfamiliar and non-economical. Their research process explores an ideal body-form, and this thesis focuses on this point. For this work, I bring the notion of 'liminality' that connotes the praxis for essential presence of the actor/actress as well as the incubating time and space nacessary for his/her rebirth. And for developing this work, I ask: Could not the actor's/actress' consciousness and the spatiotemporal dimensions (s)he meets, be possibly defined as the core of liminality, only in case that (s)he requires them in the process of, either exploring the unfamiliar body or familiarising with the unfamiliar body-form? As I mentioned above, the three frontiers' theatrical journey is similar in part. For example, three all start from the actor's/actress' consciousness and then go through the body enlarged with it. Then they continue their journey, but different from one another. Meyerhold still uses the conscious body. But now he transforms it into a kind of mobilized sculptures. In comparison with Meyerhold's use of the consciousness, Grotowsky puts his emphasis on an autonomous body which, if necessary, cast away even the innate consciousness. Likewise, to Barba, theatre always starts from the actor/actress who has already taken off all kinds of conventions. (Conventions should be re-designed!) The actor/actress therefore recreates him/herself as his/her body-mind wears a new, unfamiliar, readjusted form and vitality. And then this restructured body-mind may unceasingly aim at exploring its vitalized 'positive organism', that is the waves of self-centering energy, an existential nuance, and an authentic (or maybe behavioral) expressiveness. Now it seems clear that the liminal process for the frontiers' theatrical journey could be equalized as a profound process of self-penetration, self-transformation, and self-realization. This thesis explores the mystic realm of liminality.

Comparative Analysis and Performance Evaluation of New Low-Power, Low-Noise, High-Speed CMOS LVDS I/O Circuits (저 전력, 저 잡음, 고속 CMOS LVDS I/O 회로에 대한 비교 분석 및 성능 평가)

  • Byun, Young-Yong;Kim, Tae-Woong;Kim, Sam-Dong;Hwang, In-Seok
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.45 no.2
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    • pp.26-36
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    • 2008
  • Due to the differential and low voltage swing, Low Voltage Differential Signaling(LVDS) has been widely used for high speed data transmission with low power consumption. This paper proposes new LVDS I/O interface circuits for more than 1.3 Gb/s operation. The LVDS receiver proposed in this paper utilizes a sense amp for the pre-amp instead of a conventional differential pre-amp. The proposed LVDS allows more than 1.3 Gb/s transmission speed with significantly reduced driver output voltage. Also, in order to further improve the power consumption and noise performance, this paper introduces an inductance impedance matching technique which can eliminate the termination resistor. A new form of unfolded impedance matching method has been developed to accomplish the impedance matching for LVDS receivers with a sense amplifier as well as with a differential amplifier. The proposed LVDS I/O circuits have been extensively simulated using HSPICE based on 0.35um TSMC CMOS technology. The simulation results show improved power gain and transmission rate by ${\sim}12%$ and ${\sim}18%$, respectively.

Analysis on the Current status of e-Learning among Pre-Service Teachers (예비교사의 이러닝 인식 및 사용 교수·학습 전략 실태 분석)

  • Lee, Okhwa;Jo, Miheon
    • The Journal of Korean Association of Computer Education
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    • v.7 no.6
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    • pp.95-105
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    • 2004
  • It is important to understand how pre-service teachers perceive e-learning because their prior-experience with e-learning will have a great impact on their teaching after the graduation. Pre-service teachers (401 students) with cyber learning experience, which is a form of e-learning, were selected in 2004 in May and June. Survey was conducted regarding the instructional experience (working hours, tasks and evaluation, satisfaction about cyber learning and its academic achievement, difficulties and suggestions) and instructional methods (instructional activities, frequencies of interaction, strategies of interaction, collaborative activities, behaviors in the group instructional activities for knowledge development). The results are pre-service teachers tent to spend similar v slightly less working hours for cyber learning, similar or slightly less satisfaction level for the instruction and the academic achievement. It was interesting that female students were more negative than males students, considering female students have been more active in online discussion traditionally. Logical presentation of contents and instructional strategies for the cyber learning were the most wanting suggestions. E-mails and BBS for reference materials were the two most used functions in the online learning. The amount and types of tasks were satisfactory. Students did not interact freely during the group activities, they reported they did not learn much through the group activity. During the group work, they consider they do their roles with responsibility while they have slightly negative responses toward other members' contribution in the group activity. Off line meeting is strongly suggested.

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A Study on the Potential and Limitation of Pre-producing Dramas through Social Analysis -focusing on a jtbc drama - (소셜 분석을 통한 사전제작 드라마의 가능성과 한계에 관한 연구 -jtbc <맨투맨>을 중심으로-)

  • Kim, Kyung-Ae;Ku, Jin-Hee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.2
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    • pp.164-172
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    • 2018
  • This paper examines the relevance of pre-production and storytelling in big data analysis and, focusing on JTBC's Man to Man series, looks at how the drama's storytelling should be structured. In this study, we conducted text mining on blogs focused on a particular topic to read the viewer's thoughts on pre-produced dramas and on 67 blogs written about Pre-Production Dramas from 2016.12.15 to 2017.12.15. Also, we conducted sentiment analysis about the Man to Man series, which is not only a pre-production drama, but also has storytelling issues. The blog text extraction and text mining were analyzed using the OutWit Hub and the R, and the tools.provided by social metrics were used to make sentiment analyses of the larger data. Sentiment analysis revealed that the viewers of the Man to Man series did not agree with the romance between Kim Sul-woo and Cha Do-ha, due to the lack of reality in the female characters. Therefore, it was concluded that it is crucial to increase the reality of the characters in order to increase the audience's empathy. These studies will continue to be necessary, because they will form the basis for digitally driven storytelling studies and will provide valuable materials for conducting predictions and instructions in the cultural content industry.

Local Buckling Strength of PFRP I-Shape Compression Members Obtained by LRFD Design Method and Closed-Form Solution (하중저항계수설계법 및 정밀해법에 의한 PFRP I형 단면 압축재의 국부좌굴강도)

  • Choi, Jin-Woo;Seo, Su-Hong;Joo, Hyung-Joong;Yoon, Soon-Jong
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.5 no.2
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    • pp.1-8
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    • 2014
  • Fiber reinforced polymeric plastic (FRP) materials have many advantages over conventional structural materials, i.e., high specific strength and stiffness, high corrosion resistance, right weight, etc. Among the various manufacturing methods, pultrusion process is one of the best choices for the mass production of structural plastic members. Since the major reinforcing fibers are placed along the axial direction of the member, this material is usually considered as an orthotropic material. However, pultruded FRP (PFRP) structural members have low modulus of elasticity and are composed of orthotropic thin plate components the members are prone to buckle. Therefore, stability is an important issue in the design of the pultruded FRP structural members. Many researchers have conducted related studies to publish the design method of FRP structures and recently, referred to the previous researches, pre-standard for LRFD of pultruded FRP structures is presented. In this paper, the accuracy and suitability of design equation for the local buckling strength of pultruded FRP I-shape compression members presented by ASCE are estimated. In the estimation, we compared the results obtained by design equation, closed-form solution, and experiments conducted by previous researches.

The Grid and Axis in Modern Architecture From Durand to Le Corbusier (현대건축에서 그리드와 축에 관한 연구 -듀랑에서부터 르 코르뷔제까지-)

  • Pai, Hyung-Min
    • Journal of architectural history
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    • v.11 no.4 s.32
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    • pp.99-115
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    • 2002
  • Centered on Durand and Le Corbusier, this study analyses the changing status of the grid and axis in modern architecture. In the Renaissance, the taxis grid operated as a contour grid, defining the elements and space of the building as part of closed harmonized world. In his Pre'cis des lec., ons d'architecture, Durand provides the most explicit demonstration of a new modem grid in which its lines function as spatial and structural axes. In principle these axes are coordinates for the placements of a priori elements but in Beaux-Arts practice, as Durand himself acknowledged, they involve a simultaneous process in which the spatial axis sets up the basic parti and the structural axis is developed into the building's poche'. As a coordinate, Durand's grid provides a place for the 'subject' to enter the architectural process. At the same time, it is the object of the subject's gaze, the dense site of the subject's transformative actions. Though Le Corbusier is noted for his frequent attacks on the academic system, his architecture should be seen within the continuity of the classical tradition. He redefines the Beaux-Arts axis as a moving and seeing observer, and continues the discipline of the plan, the essential discipline of the Beaux-Arts system. In his dialectics, an intellectual scheme which extends to his commentators, the intention and will of the subject must come in tune with the objective material form of the building. Like Durand, Le Corbusier's axis provides the medium for the subject to enter. Unlike the Beaux-Arts system, however, Le Corbusier's mobile subject no longer has a holistic view of the building previously provided by the central axis. If there is a parti for Le Corbusier, it consists of the domino grid as a potential, but nonetheless, tangible form. In comparison with the Beaux-Arts structural grid, his gaze no longer lingers on their lines because they no longer constitute a formal process tied to the development of a thick articulated structure. Le Corbusier's grid constitutes a 'loose' form, one that breaks down the hierarchical nature of the Beaux-Arts system.

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