• Title/Summary/Keyword: dynamic modification

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Seismic Performance Evaluation of Steel Moment Frames in Korea Using Nonlinear Dynamic Analysis (비선형동적해석을 통한 국내 철골 모멘트골조의 내진성능 평가)

  • Kim, Tae-Wan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.16 no.4
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    • pp.1-8
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    • 2012
  • Domestic steel moment resisting frames were designed in accordance with the former KBC2005 and the current KBC2009, and then their seismic performance was evaluated in accordance with FEMA355F by utilizing nonlinear dynamic analysis. The results from the procedure in FEMA355F were different with those from the capacity spectrum method utilizing nonlinear static push-over analysis. In particular, the domestic steel moment resisting frames have a weak panel zone, so their behavior can be estimated more precisely by nonlinear dynamic analysis. The domestic steel moment resisting frames satisfied the performance goal if located at a site class $S_B$ or $S_C$, regardless of the story number and the response modification factor. However, if they are located at a site class $S_D$ or $S_E$, performance goal satisfaction cannot be guaranteed. No matter what standard is used for the design, KBC2005 or KBC2009, the domestic steel moment resisting frames may possess satisfactory seismic performance if the site condition is relatively good.

Dynamic Analysis Framework for Cryptojacking Site Detection (크립토재킹 사이트 탐지를 위한 동적 분석 프레임워크)

  • Ko, DongHyun;Jung, InHyuk;Choi, Seok-Hwan;Choi, Yoon-Ho
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.28 no.4
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    • pp.963-974
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    • 2018
  • With the growing interest in cryptocurrency such as bitcoin, the blockchain technology has attracted much attention in various applications as a distributed security platform with excellent security. However, Cryptojacking, an attack that hijack other computer resources such as CPUs, has occured due to vulnerability to the Cryptomining process. In particular, browser-based Cryptojacking is considered serious because attacks can occur only by visiting a Web site without installing it on a visitor's PC. The current Cryptojacking detection system is mostly signature-based. Signature-based detection methods have problems in that they can not detect a new Cryptomining code or a modification of existing Cryptomining code. In this paper, we propose a Cryptojacking detection solution using a dynamic analysis-based that uses a headless browser to detect unknown Cryptojacking attacks. The proposed dynamic analysis-based Cryptojacking detection system can detect new Cryptojacking site that cannot be detected in existing signature-based Cryptojacking detection system and can detect it even if it is called or obfuscated by bypassing Cryptomining code.

A Dynamic Map Partition for Load Balancing of MMORPG based on Virtual Area Information (MMORPG에서의 부하 분산을 위한 가상 영역 정보 기반 동적 지역 분할)

  • Kim Beob-Kyun;An Dong-Un;Chung Seung-Jong
    • The KIPS Transactions:PartA
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    • v.13A no.3 s.100
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    • pp.223-230
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    • 2006
  • A MMORPG(Massively Multiplayer Online Role-Playing Game) is an online role-playing game in which a large number of players can interact with each other in the same world at the same time. Most of them require significant hardware requirements(e.g., servers and bandwidth), and dedicated support staff. Despite the efforts of developers, users often cite overpopulation, lag, and poor support as problems of games. In this paper, a dynamic load balancing method for MMORPGS is proposed. It tries to adapt to dynamic change of population by using dynamic map-partition method with VML(Virtual Map Layer) which consists of fields, sector groups, sectors, and cells. From the experimental results, our approach achieves about $23^{\sim}67%$ lower loads for each field server. By the modification to Virtual Area Layer, we can easily manage problems that come from changes of map data, resources' status, and users' behavior pattern.

Application of Dynamic Regulation to Increase L-Phenylalanine Production in Escherichia coli

  • Wu, Jie;Liu, Yongfei;Zhao, Sheng;Sun, Jibin;Jin, Zhaoxia;Zhang, Dawei
    • Journal of Microbiology and Biotechnology
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    • v.29 no.6
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    • pp.923-932
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    • 2019
  • Current strategies of strain improvement processes are mainly focused on enhancing the synthetic pathways of the products. However, excessive metabolic flux often creates metabolic imbalances, which lead to growth retardation and ultimately limit the yield of the product. To solve this problem, we applied a dynamic regulation strategy to produce $\text\tiny{L}$-phenylalanine ($\text\tiny{L}$-Phe) in Escherichia coli. First, we constructed a series of Phe-induced promoters that exhibited different strengths through modification of the promoter region of tyrP. Then, two engineered promoters were separately introduced into a Phe-producing strain xllp1 to dynamically control the expression level of one pathway enzyme AroK. Batch fermentation results of the strain xllp3 showed that the titer of Phe reached 61.3 g/l at 48 h, representing a titer of 1.36-fold of the strain xllp1 (45.0 g/l). Moreover, the $\text\tiny{L}$-Phe yields on glucose of xllp3 (0.22 g/g) were also greatly improved, with an increase of 1.22-fold in comparison with the xllp1 (0.18 g/g). In summary, we successfully improved the titer of Phe by using dynamic regulation of one key enzyme and this strategy can be applied for improving the performance of strains producing other aromatic amino acids and derived compounds.

A remote device authentication scheme in M2M communications (M2M 통신에서 원격장치 인증 기법)

  • Lee, Song-Hee;Park, Nam-Sup;Lee, Keun-Ho
    • Journal of Digital Convergence
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    • v.11 no.2
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    • pp.309-316
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    • 2013
  • Machine-to-machine (M2M) communication occurs when devices exchange information independent of human intervention. Prominent among the technical challenges to M2M communication are security issues, such as eavesdropping, spoofing, modification, and privacy violation. Hence, it is very important to establish secure communication. In this paper, we propose a remote authentication scheme, based on dynamic ID, which provides secure communication while avoiding exposure of data through authentication between the M2M domain and the network domain in the M2M architecture. We then prove the correctness and security of the proposed scheme using a logic-based formal method.

Institutional Applications of Eclipse Scripting Programming Interface to Clinical Workflows in Radiation Oncology

  • Kim, Hojin;Kwak, Jungwon;Jeong, Chiyoung;Cho, Byungchul
    • Progress in Medical Physics
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    • v.28 no.3
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    • pp.122-128
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    • 2017
  • Eclipse Scripting Application Programming Interface (ESAPI) was devised to enhance the efficiency in such treatment related workflows as contouring, treatment planning, plan quality measure, and data-mining by communicating with the treatment planning system (TPS). It is provided in the form of C# programming based toolbox, which could be modified to fit into the clinical applications. The Scripting program, however, does not offer all potential functionalities that the users intend to develop. The shortcomings can be overcome by combining the Scripting programming with user-executable program on Windows or Linux. The executed program has greater freedom in implementation, which could strengthen the ability and availability of the Scripting on the clinical applications. This work shows the use of the Scripting programming throughout the simple modification of the given toolbox. Besides, it presents the implementation of combining both Scripting and user-executed programming based on MATLAB, applied to automated dynamic MLC wedge and FIF treatment planning procedure for promoting the planning efficiency.

An XY scanner with minimized coupling motions for the high speed AFM (상호 간섭이 최소화된 고속 원자현미경용 XY 스캐너 제작)

  • Park J.;Moon W.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.653-656
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    • 2005
  • This paper introduces design, fabrication and experiment process of a novel scanner for the high speed AFM(Atomic Force Microscope). A proper design modification is proposed through analyses on the dynamic characteristics of the existing linear motion stages using a dynamic analysis program, Recurdyn. Since the scanning speed of each direction is allowed to be different, the linear motion stage for the high-speed scanner of AFM can be so designed to have different resonance frequencies for the modes with one dominant displacement in the desired directions. One way to achieve this objective is to use one-direction flexure mechanism for each direction and to mount one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separates the frequencies of the two vibration modes with one dominant displacement in each desired direction, hence, the coupling between the motions in the two directions. In addition, a pair of actuators is used for each axis to decrease the cross talks in the two motions and gives a force large enough to actuate the slow motion stage, which carries the fast motion stage. After these design modifications, a novel scanner with scanning speed higher than 10 Hz can be achieved to realize undistorted images in the high speed AFM.

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A New Ensemble System using Dynamic Weighting Method (동적 중요도 결정 방법을 이용한 새로운 앙상블 시스템)

  • Seo, Dong-Hun;Lee, Won-Don
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.6
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    • pp.1213-1220
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    • 2011
  • In this paper, a new ensemble system using dynamic weighting method with added weight information into classifiers is proposed. The weights used in the traditional ensemble system are those after the training phase. Once extracted, the weights in the traditional ensemble system remain fixed regardless of the test data set. One way to circumvent this problem in the gating networks is to update the weights dynamically by adding processes making architectural hierarchies, but it has the drawback of added processes. A simple method to update weights dynamically, without added processes, is proposed, which can be applied to the already established ensemble system without much of the architectural modification. Experiment shows that this method performs better than AdaBoost.

Trajectory Tracking Control of a Real Redundant Manipulator of the SCARA Type

  • Urrea, Claudio;Kern, John
    • Journal of Electrical Engineering and Technology
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    • v.11 no.1
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    • pp.215-226
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    • 2016
  • Modeling, control and implementation of a real redundant robot with five Degrees Freedom (DOF) of the SCARA (Selective Compliant Assembly Robot Arm) manipulator type is presented. Through geometric methods and structural and functional considerations, the inverse kinematics for redundant robot can be obtained. By means of a modification of the classical sliding mode control law through a hyperbolic function, we get a new algorithm which enables reducing the chattering effect of the real actuators, which together with the learning and adaptive controllers, is applied to the model and to the real robot. A simulation environment including the actuator dynamics is elaborated. A 5 DOF robot, a communication interface and a signal conditioning circuit are designed and implemented for feedback. Three control laws are executed in: a simulation structure (together with the dynamic model of the SCARA type redundant manipulator and the actuator dynamics) and a real redundant manipulator of the SCARA type carried out using MatLab/Simulink programming tools. The results, obtained through simulation and implementation, were represented by comparative curves and RMS indices of the joint errors, and they showed that the redundant manipulator, both in the simulation and the implementation, followed the test trajectory with less pronounced maximum errors using the adaptive controller than the other controllers, with more homogeneous motions of the manipulator.

LES Studies on Flow Structure and Flame Characteristic with Equivalence Ratios in a Swirling Premixed Combustor (선회 예혼합연소기에서 당량비 변화에 따른 유동구조 및 화염특성에 관한 LES 연구)

  • Hwang, Cheol-Hong;Kim, Se-Won;Lee, Chang-Eon
    • Journal of the Korean Society of Combustion
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    • v.11 no.4
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    • pp.27-35
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    • 2006
  • The impacts of equivalence ratio on flow structure and flame dynamic in a model gas turbine combustor are investigated using large eddy simulation(LES). Dynamic k-equation model and G-equation flamelet model are employed as LES subgrid model for flow and combustion, respectively. As a result of mean flow field for each equivalence ratio, the increase of equivalence ratio brings about the decrease of swirl intensity through the modification of thermal effect and viscosity, although the same swirl intensity is imposed at inlet. The changes of vortical structure and turbulent intensity etc. near flame surface are occurred consequently. That is, the decrease of equivalence ratio can leads to the increase of heat release fluctuation by the more increased turbulent intensity and fluctuation of recirculation flow. In addition, the effect of inner vortex generated from vortex breakdown on the heat release fluctuation is increased gradually with the decrease of equivalence ratio. Finally, it can be identified that the variations of vortical structure play an important role in combustion instability, even though the small change of equivalence ratio is occurred.

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