• Title/Summary/Keyword: software engineering

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Numerical Analysis for Separation of Methane by Hollow Fiber Membrane with Cocurrent Flow (병류흐름 중공사 분리막에 의한 메탄 분리 수치해석)

  • Lee, Seungmin;Seo, Yeonhee;Kang, Hanchang;Kim, Jeonghoon;Lee, Yongtaek
    • Korean Chemical Engineering Research
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    • v.53 no.3
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    • pp.295-301
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    • 2015
  • A theoretical analysis was carried out to examine the concentration behavior of methane from a biogas using a polysulfone membrane. After the governing equations were derived for the cocurrent flow mode in a membrane module, the coupled nonlinear differential equations were numerically solved with the Compaq Visual Fortran 6.6 software. At the typical operating condition of mole fraction of 0.7 in a feed stream, the mole fraction of methane in the retentate increased to 0.76 while the normalized retentate flow rate to the feed flow rate decreased from 1 to 0.79. When either the mole fraction of methane in a feed increased or the pressure of the feed stream increased, the methane mole fraction in the retentate increased. On the other hand, it was found that as either the membrane area decreased or the ratio of the permeate pressure to the feed pressure increased, the methane mole fraction in the retentate decreased. In case that the stage cut increased, the methane mole fraction in the retentate increased while the recovery of methane slightly decreased.

COBie Based Maintenance Document Generation of Railway Track (COBie 기반 철도 선로유지관리 문서 생성)

  • Seo, Kyung-Wan;Kwon, Tae-Ho;Lee, Sang-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.4
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    • pp.307-312
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    • 2017
  • In this study, we proposed a method to generate a maintenance documents for railway track through Construction Operations Building information exchange(COBie) which is a subset of Industry Foundation Classes(IFC), a data model for Building Information Modeling(BIM). In order to define the items necessary for railway track maintenance document generation, we analyzed the guideline of maintenance and management to track by the Ministry of Land, Infrastructure and Transport(MLTM), and defined the way to refer to the information items in the COBie spreadsheet. The additional properties not supported in IFC, were created for generation of an Information model that reflecting maintenance information items of railway track by applying user-defined property set within the IFC framework. An IFC-based Information model reflecting the user-defined property was implemented through BIM software, and rail track maintenance information items were transferred to COBie spreadsheet according to the defined approach. It is tested that the information can be transferred from the IFC-based as-built model to the COBie spreadsheet, which can be used to generate the necessary documents for railway facility maintenance work.

Implementation of a Network Simulator for Cyber Attacks and Detections based on SSFNet (SSFNet 기반 사이버 공격 및 탐지를 위한 네트워크 시뮬레이터의 구현)

  • Shim, Jae-Hong;Jung, Hong-Ki;Lee, Cheol-Won;Choi, Kyung-Hee;Park, Seung-Kyu;Jung, Gi-Hyun
    • Journal of KIISE:Computing Practices and Letters
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    • v.8 no.4
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    • pp.457-467
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    • 2002
  • In order to simulate cyber attacks and predict network behavior by attacks, we should represent attributes of network components in the simulation model, and should express characteristics of systems that carry out various cyber attacks and defend from these attacks. To simulate how network load may change under the cyber attacks, we extended SSF[9, 10] that is process-based event-oriented simulation system. We added a firewall class and a packet manipulator into the SSFNet that is a component of SSF. The firewall class, which is related to the security, is to simulate cyber attacks, and the packet manipulator is a set of functions to write attack programs for the simulation. The extended SSFNet enables to simulate a network with the security systems and provides advantages that make easy to port already exsiting attack programs and apply them to the simulation evironment. We made a vitual network model to verify operations of the added classes, and simulated a smurf attack that is a representative denial of sevive attack, and observed the network behavior under the smurf attack. The results showed that the firewall class and packet manipulator developed in this paper worked normaly.

Implementation and Validation of EtherCAT Support in Integrated Development Environment for Synchronized Motion Control Application (동기 모션 제어 응용을 위한 통합개발환경의 EtherCAT 지원 기능 구현 및 검증)

  • Lee, Jongbo;Kim, Chaerin;Kim, Ikhwan;Kim, Youngdong;Kim, Taehyoun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.2
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    • pp.211-218
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    • 2014
  • Recently, software-based programmable logic controller (PLC) systems, which are implemented in standard PLC languages on general hardware, are gaining popularity because they overcome the limitations of classical hardware PLC systems. Another noticeable trend is that the use of integrated development environment (IDE) is becoming important. IDEs can help developers to easily manage the growing complexity of modern control systems. Furthermore, industrial Ethernet, e.g. EtherCAT, is becoming widely accepted as a replacement for conventional fieldbuses in the distributed control domain because it offers favorable features such as short transmission delay, high bandwidth, and low cost. In this paper, we implemented the extension of open source IDE, called Beremiz, for developing EtherCAT-based real-time, synchronized motion control applications. We validated the EtherCAT system management features and the real-time responsiveness of the control function by using commercial EtherCAT drives and evaluation boards.

Development of an Automated Design Algorithm for the Longitudinal Members of Oil Tankers based on H-CSR (H-CSR 기반 유조선 종강도 부재의 설계 자동화 알고리즘 개발)

  • Park, Chan-im;Jeong, Sol;Song, Ha-cheol;Na, Seung-soo;Park, Min-cheol;Shin, Sang-hoon;Lee, Jeong-youl
    • Journal of the Society of Naval Architects of Korea
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    • v.53 no.6
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    • pp.503-513
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    • 2016
  • In order to reduce the green-house gas exhaustion, International Maritime Organization (IMO) has been reinforcing carbon gas regulations. Due to the regulations, a lot of competitions for designing Eco ship in the shipbuilding industry are progressing now. It is faced with the necessity of reducing hull weight by combining automated systems for optimal compartment arrangement with hull structural design. Most researches on optimum structural design method have been consistently in progress and applied to minimize weight and cost of mid-ship section in preliminary ship design stage based on analytical structural analysis method on fixed compartment arrangement. In order to reduce design period and to improve international technical competitiveness by shortening the period of hull structural design and enhancing design accuracy, it has been felt necessity to combine optimized compartment arrangement with optimum design of ship structure based on the international regulations and rules. So in this study, the automated design algorithm for longitudinal members has been developed to combine automated algorithm of compartment arrangement with hull structural design system for oil tanker. The SeaTrust-Hullscan software developed by Korean Register is used to perform ship structural design for mother ship and selected design cases. The effect of weight reduction is verified with comparison of ship weight between mother ship and the cases suggested in this study.

Analysis of the 2-dimensional marginal fit of the occlusal surface and the 3-dimensional accuracy of the inner surface of the occlusal surface according to the inlay prosthesis structure made of composite resin (복합레진으로 제작한 인레이 보철물 구조에 따른 교합면 부위의 2차원 변연 적합도 및 내면 부위의 3차원 정확성 분석)

  • Kim, Dong-Yeon;Lee, Tae-Hee;Park, Dong-In;Park, Jin-Young;Jeong, Il-Do;Lee, Ha-Na;Kim, Ji-Hwan;Kim, Woong-Chul
    • Journal of Technologic Dentistry
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    • v.41 no.1
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    • pp.21-27
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    • 2019
  • Purpose: To evaluate 2D and 3D of occulsal, mesial-occlusal and mesial-occlusal-distal cavity of composite resin inlay. Methods: Abutment tooth 16, 36 of FDI system was selected for the study. Inlay prostheses classified as occlusal cavity (OC group), mesial-occlusal (MOC) and mesial-occlusal-distal cavity (MODC) were prepared using composite resin. Composite resin was injected with composite resin in prepared tooth cavity and then photopolymerized with UV light. Additional thermal polymerization was performed. Marginal gap of composite resin inlays were measured by digital microscope(x160) with silicone replica technique. The data was analyzed from statistical software for Kruskal-Wallis test (${\alpha}=0.05$). 3-dimensional analysis was analyzed through superimposition method. Results: The smallest 2D marginal fit measure of the three groups was $47.0{\pm}21.6{\mu}m$ in the MOC group. The largest 2D marginal was $69.1{\pm}33.8{\mu}m$ in the MODC group. In the trueness of the three groups, the most accurate figure was $14.4{\pm}2.3{\mu}m$ for the MODC group. In Precision, the most accurate figure was $14.5{\pm}4.3{\mu}m$ for the MODC group. Conclusion : In this study, 2D marginal fit of OC, MOC, and MODC cavities fabricated with composite resin was applicable to all clinical applications. In the 3D inner surface accuracy evaluation, the MODC group showed the accuracy results.

A Study on the Implementation and Modeling of 20kW Scale ESS Load Test Device for Emergency Generator (소방용 비상발전기의 현장부하시험을 위한 20 kW급 ESS 부하시험장치 모델링과 구현에 관한 연구)

  • Choi, Seung-Kyou;Lee, Hu-Dong;Choi, Sung-Sik;Ferreira, Marito;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.9
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    • pp.541-550
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    • 2019
  • An emergency generator is key equipment for fire-fighting to supply power to fire-fighting facilities, which protect property and people in cases of fire accidents. A rated load test for emergency generators must be carried out by connecting an emergency load to the generator in accordance with related regulations. However, a no-load test has been performed for emergency generators in general since serious problems can occur when the main power is cut off, including the damage of customer devices and shut down of critical loads. Therefore, this paper proposes a load test method for an emergency generator using energy storage system (ESS) without the interruption of main power. The emergency power system was also modeled based on PSCAD/EMTDC software, and a 200-kW scale ESS load test device was implemented. The simulation and test results show that the load test method is useful and practical for an emergency power supply system.

Behavioral Characteristics and Safety Management Plan for Fill Dam During Water Level Fluctuation Using Numerical Analysis (수치해석을 이용한 수위변동시 필댐의 거동특성 및 안전관리방안)

  • Jung, Heedon;Kim, Yongseong;Lee, Moojae;Lee, Seungjoo;Tamang, Bibek;Heo, Joon;Ahn, Sungsoo
    • Journal of the Korean Geosynthetics Society
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    • v.20 no.1
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    • pp.45-55
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    • 2021
  • In this study, the behavioral characteristics of the fill dam were analyzed during water level fluctuations through a numerical analysis model, and the reservoir safety management plan was prepared. The variation in plastic deviatoric strain, horizontal displacement, stress path, pore water pressure, etc., due to elevation of water level in the upper and lower sides of shell and core were analyzed using numerical analysis software, viz. GTS NX and LIQCA. The analysis results manifest that as the water level in the dam body increases rapidly, the pore water pressure and displacement also increase quickly. It was found that the elevation of the water level causes an increase in pore water pressure in the dam body as well as an increase in the saturation of the dam body and decreased effective stress. It is considered that this type of dam behavior can be the cause of the reduction of strength and stiffness of the dam. Also, it is assumed that the accumulated plastic deviatoric strain due to the deformation of the dam body caused by water infiltration causes an increase in displacement. Based on these experimental results and the results of analyses of the existing reservoir safety diagnosis techniques, an improvement plan for dam safety diagnosis and evaluation criteria was proposed, and these results can be used as primary data while revising dam safety diagnosis guidelines.

Seismic investigation of cyclic pushover method for regular reinforced concrete bridge

  • Shafigh, Afshin;Ahmadi, Hamid Reza;Bayat, Mahmoud
    • Structural Engineering and Mechanics
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    • v.78 no.1
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    • pp.41-52
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    • 2021
  • Inelastic static pushover analysis has been used in the academic-research widely for seismic analysis of structures. Nowadays, the variety pushover analysis methods have been developed, including Modal pushover, Adaptive pushover, and Cyclic pushover, in which some weaknesses of the conventional pushover method have been rectified. In the conventional pushover analysis method, the effects of cumulative growth of cracks are not considered on the reduction of strength and stiffness of RC members that occur during earthquake or cyclic loading. Therefore, the Cyclic Pushover Analysis Method (CPA) has been proposed. This method is a powerful technique for seismic evaluation of regular reinforced concrete buildings in which the first mode of them is dominant. Since the bridges have different structures than buildings, their results cannot necessarily be attributed to bridges, and more research is needed. In this study, a cyclic pushover analysis with four loading protocols (suggested by valid references) by the Opensees software was conducted for seismic evaluation of two regular reinforce concrete bridges. The modeling method was validated with the comparison of the analytical and experimental results under both cyclic and dynamic loading. The failure mode of the piers was considered in two-mode of flexural failure and also a flexural-shear failure. Along with the cyclic analysis, conventional analysis has been studied. Also, the nonlinear incremental dynamic analysis (IDA) method has been used to examine and compare the results of pushover analyses. The time history of 20 far-field earthquake records was used to conduct IDA. After analysis, the base shear vs. displacement in the middle of the deck was drawn. The obtained results show that the cyclic pushover analysis method is able to evaluate an accurate seismic behavior of the reinforced concrete piers of the bridges. Based on the results, the cyclic pushover has proper convergence with IDA. Its accuracy was much higher than the conventional pushover, in which the bridge piers failed in flexural-shear mode. But, in the flexural failure mode, the results of each two pushover methods were close approximately. Besides, the cyclic pushover method with ACI loading protocol, and ATC-24 loading protocol, can provided more accurate results for evaluating the seismic investigation of the bridges, specially if the bridge piers are failed in flexural-shear failure mode.

A Security SoC embedded with ECDSA Hardware Accelerator (ECDSA 하드웨어 가속기가 내장된 보안 SoC)

  • Jeong, Young-Su;Kim, Min-Ju;Shin, Kyung-Wook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.7
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    • pp.1071-1077
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    • 2022
  • A security SoC that can be used to implement elliptic curve cryptography (ECC) based public-key infrastructures was designed. The security SoC has an architecture in which a hardware accelerator for the elliptic curve digital signature algorithm (ECDSA) is interfaced with the Cortex-A53 CPU using the AXI4-Lite bus. The ECDSA hardware accelerator, which consists of a high-performance ECC processor, a SHA3 hash core, a true random number generator (TRNG), a modular multiplier, BRAM, and control FSM, was designed to perform the high-performance computation of ECDSA signature generation and signature verification with minimal CPU control. The security SoC was implemented in the Zynq UltraScale+ MPSoC device to perform hardware-software co-verification, and it was evaluated that the ECDSA signature generation or signature verification can be achieved about 1,000 times per second at a clock frequency of 150 MHz. The ECDSA hardware accelerator was implemented using hardware resources of 74,630 LUTs, 23,356 flip-flops, 32kb BRAM, and 36 DSP blocks.