• Journal of the Korean Chemical Society
• /
• v.31 no.6
• /
• pp.534-541
• /
• 1987

The study of reaction mechanism for the substitution of ethylenediamine (en) for Cl and Hedta from $[CoCl(Hedta)]^-$ in the presence of $Hg^{2+}$ ion was carried out by uv and CD spectra. From the kinetic data, we proposed that the first ethylenediamine be substituted through the associative reaction path by means of interaction of $Hg^{2+}$ ion with Co(III), and that the second and the third ethylenediamine be substituted stepwise. From the optical purities of $[Co(en)_3]^{3+}$ which was formed after reaction, we suggested the critical stereochemical step and new substitution reaction paths.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2007.11a
• /
• pp.647-651
• /
• 2007

The Lean Construction is adopted from Lean Principle of Manufacturing Industry in the early of 1990, that has been providing theoretical background and good practical implementation for maximizing customers' satisfaction and improving productivity through minimizing the waste factors in the construction operations. The Last Planner System(LPS), one of the elementary techniques of Lean Construction, aims for improving the work reliability and reducing variability by measuring and managing the daily or weekly performance for overcoming the weakness of recent complex schedule management tools such as Critical Path Method. This research is propose a framework for implementation of LPS conducted by owner in plant construction.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.5
• /
• pp.636-642
• /
• 1999

The synthesis of the 3D images is the most important part of the virtual reality. The ray tracing is the best method for reality in the 3D graphics. But the ray tracing requires long computation time for the synthesis of the 3D images. So, we implement the ray tracing with software and hardware. Specially we design the hit-test unit with FPGA tool for the ray tracing. Hit-test unit is a very important part of ray tracing to improve the speed. In this paper, we proposed a new hit-test algorithm and apply the parallel architecture for hit-test unit to improve the speed. We optimized the arithmetic unit because the critical path of hit-test unit is in the multiplication part. We used the booth algorithm and the baugh-wooley algorithm to reduce the partial product and adapted the CSA and CLA to improve the efficiency of the partial product addition. Our new Ray tracing processor can produce the image about 512ms/F and can be adapted to real-time application with only 10 parallel processors.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.13 no.4
• /
• pp.660-669
• /
• 1989

The strain distribution in a wide strip drawn through a wedge-shaped die is obtained from the numerical integration of strain increments along the flow path of material points in the slipline field for a non-hardening material under the plane strain condition. It is shown that the strain in the surface layer increases with friction and that the strain at the mid-plane is a function of area reduction only. The redundant deformation factor, obtained from the average strain in a drawn strip, increases with friction. For the workability analysis of a strip drawing process, the strain states along with hydrostatic stresses are needed for the evaluation of a damage function based on the hole-growth mechanism of ductile fracture. The critical maximum of the damage function is assumed to be a material constant. As a result, mid-plane cracking is likely to occur in a process at a small reduction, with a large die angle, and in poor lubrication. Distortions of an initially transverse line are also calculated.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.174.1-174.1
• /
• 2012

현재 인공위성 개발 프로젝트들을 계획하고 일정계획을 수립하기위해 간트차트가 널리 활용되고 있다. 간트차트는 프로젝트의 각 작업들이 언제 시작하고 종료되는지에 대한 작업 일정을 막대 도표를 이용하여 표시하는 프로젝트 일정표로 다양한 형태로 변경하여 사용할 수 있으나 작업경로를 표시할 수 없으며 계획의 변화에 대한 적응성이 약한 단점이 있다. 또한 일목요연하게 눈으로 보여줄 수 있으나 효과적인 프로젝트 관리에 중요한 활동 사이의 어떤 관계에 대한 정보를 주지 못한다. 인공위성개발과 같은 복잡한 프로젝트에 대해 간트차트와 더불어 PERT(Program evaluation and review technique)와 CPM(critical path method)과 같은 네트워크 도(Network Diagram)와 함께 사용될 수 있도록 그 이론과 활용방안에 대해 기술하고자 한다. PERT와 CPM은 큰 프로젝트를 계획하고 조정하기 위해 폭넓게 사용되는 두 가지 기법이다. PERT와 CPM을 사용하면 프로젝트 활동에 대한 그래프를 통한 도시, 프로젝트 소요시간 추정, 프로젝트 완료시간 준수를 위해 중요한 활동의 식별, 전체 프로젝트에 대한 지연 없이 가능한 각 활동의 지연시간 추정과 같은 이점이 있다. PERT와 CPM은 독립적으로 개발되었지만, 많은 공통점이 있다. 더 나아가서 둘 사이에 원래 존재했던 차이점은 많은 부분은 서로의 특징을 도입하면서 거의 사라졌다. 실제적으로 볼 때, 두 기법은 지금 같은 기법이며, 기술된 특징과 절차는 PERT분석 뿐 아니라 CPM 분석에도 적용될 수 있을 것이다.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.8
• /
• pp.1392-1397
• /
• 2008

The mechanical integrity of generator stator windings is one of the critical point because the electric power is generated and conducted to power system through these windings. De-mineralized water is used to cool stator bars during the normal operation of generator in large power plants because the water cooled method has highest cooling efficient. Water absorption of bar insulation is progressed by several causes such as generation of water leak path by corrosion, delamination of insulation by vibration, and inadequate water treatment, etc.. Reliable water absorption diagnostics of generator stator bar is important to ensure the availability of power plant and to reduce maintenance cost by generator accident. It is described that the water absorption characteristics for generator stator bar insulation used in 500MW capacity standard fossil power plant by cooling water temperature. It is verified that the management of stator cooling water temperature is one of the important factors to decrease water absorption rate of generator stator bars.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.4
• /
• pp.821-825
• /
• 2007

In this study, the single hardening model with stress history-dependent plastic potential, which has been most recently proposed based on the critical state soil mechanics and needs few model parameters, was verified for the normally, lightly, and heavily over-consolidated clayey specimens. The triaxial compression tests were strictly conducted. The predictions using the single hardening model generally agree with the measurement. The discrepancy exists on its main focusing on the principal stress rotation; however, the plastic work H and the principal stress rotation angle ${\beta}$ are found to be effective indicators of loading history for the plastic potential function of the stress path dependent materials.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.10
• /
• pp.1448-1453
• /
• 2015

In this paper, we propose an alternative method of communication to improve the reliability of in-vehicle networks by jointly using wireless communication networks. Wired Communication networks have been used in vehicles for the monitoring and the control of vehicle motion, however, the disconnection of wires or hardware fault of networks may cause a critical problem in vehicles. If the network manager detects a disconnection or faults in wired in-vehicle network like the Controller Area Network(CAN), it can redirect the communication path from the wired to the wireless communication like the Zigbee network. To show the validity and the effectiveness of the proposed in-vehicle network architecture, we implement the Electronic Stability Control(ESC) system as ECU-In-the-Loop Simulation(EILS) and verify that the control performance can be kept well even if some hardware faults like disconnection of wires occur.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.10
• /
• pp.4191-4203
• /
• 2015

WebView is a vital component in smartphone platforms like Android, Windows and iOS that enables smartphone applications (apps) to embed a simple yet powerful web browser inside them. WebView not only provides the same functionalities as web browser, it, more importantly, enables a rich interaction between apps and webpages loaded inside the WebView. However, the design and the features of WebView lays path to tamper the sandbox protection mechanism implemented by browsers. As a consequence, malicious attacks can be launched either against the apps or by the apps through the exploitation of WebView APIs. This paper presents a critical attack called Supplementary Event-Listener Injection (SEI) attack which adds auxiliary event listeners, for executing malicious activities, on the HTML elements in the webpage loaded by the WebView via JavaScript Injection. This paper also proposes an automated static analysis system for analyzing WebView embedded apps to classify the kind of vulnerability possessed by them and a solution for the mitigation of the attack.

• Journal of the Optical Society of Korea
• /
• v.17 no.1
• /
• pp.103-108
• /
• 2013

The operation of a Doppler wind LIDAR in a mobile environment is very sensitive to shocks and vibrations, which can cause critical failures such as misalignment of the optical path and damage to optical components. To be able to stabilize the LIDAR and to perform wind field measurements in motion, a shock absorption and vibration isolation system was designed and implemented. The performance of the vehicle-mounted Doppler wind LIDAR was tested in motion, first in a circular test route with a diameter of about 30 m and later in regular expressway traffic. The vibration isolation efficiency of the system was found to be higher than 82% in the main vibration area and shock dynamic deflection was smaller than maximal deflection of the isolator. The stability of the laser locking frequency in the same mobile environment before and after the vibration isolation system installation was also found to be greatly improved. The reliability of the vibration isolation system was confirmed by good results of the analysis of the LIDAR data, in particular the plane position indicator of the line of sight velocity and the wind profile.