• Journal of Korea Technology Innovation Society
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• v.3 no.2
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• pp.78-93
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• 2000

Since computerized numerical controller(CNC) emerged as a result of the fusion of the electronics technology and the mechanical technology, there has been continuous evolution of CNC technology in the mechatronics industry. The industry is recently developing a new control system based on the fusion of personal computer(PC) and CNC. Upgraded PC has now integrated into CNC, making various machines possible to exchange data, software and hardware, and to greatly improve man-machine interface. The fusion of PC and CNC can form a new paradigm in technological innovation of not only control system but also whole machinery industry in near the future. Korea lagged behind the developed countries in the development of open control system with the fusion of PC. Turbotek, Hyundai Motor and Daewoo are leading companies, but their commercial possibility seems to be low because domestic market is too small to reap a commercial benefit. Nevertheless, the development of the system is an essential step for Korea to embark on a future technological paradigm of the machinery industry. The government needs to play some role for the development, for instance, government R&D projects, institutional building and training of related technicians.

• Fisheries and Aquatic Sciences
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• v.7 no.2
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• pp.90-95
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• 2004

An analytical model for predicting the convection-diffusion of solute dumped in a homogeneous open sea of constant water depth has been developed in a time-integral form. The model incorporates spatially uniform, uni-directional, mean and oscillatory currents for horizontal convection, the settling velocity for the vertical convection, and the anisotropic turbulent diffusion. Two transformations were introduced to reduce the convection-diffusion equation to the Fickian type diffusion equation, and then the Galerkin method was then applied via the expansion of eigenfunctions over the water column derived from the Sturm-Liouville problem. A series of calculations has been performed to demonstrate the applicability of the model.

• 전기의세계
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• v.12
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• pp.6-11
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• 1963

철극형동기기를 무부하상태로 전환을 할때 갑지기 2상간에 단락이 돌발한 경우 다른 개로상단자에 유기되는 open-phase voltage의 과도상태를 구명하는데 본 논문의 목적이 있다. 우선 전기자전압의 직축분과 횡축분을 구하기 위하여 Blondel씨가 제창한 이론을 matrix form으로 전개하여 그의 기본전압방정식을 확립시키고 이어서 상간단락전류를 구해가지고 개로상단자에 유기되는 이상전압, 즉 open-phase voltage의 치를 e$_{a}$ =e$_{d}$cos.theta.-e$_{q}$ sin.theta.+e$_{0}$의 관계식에 의거해서 구해보자는 것이다. 논설상의 편의를 도모키 위해 몇가지 가정을 마련하는 것이 순서라고 본다. 제동권선이 없는 철극동기기를 취급하고 포화현상을 무시하며 직축상에 주계자가 존재하는것으로 간주하며, 전기자회로의 저항은 근소치임으로 시정수에 한애서만 영향을 주는 것 이외에는 계산상에서 이를 무시하고 역시 계산에 나오는 무든 양은 per-unit notation을 사용하고 영상분은 고려하지 않으며 대표적인 동기기정수를 x$_{d}$=0.78, x'$_{d}$=0.21, x$_{q}$ =0.48 및 E=1로 정해서 구명해보자는 것이다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.233-238
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• 2000

CNC machine tool is assembled by central processor, PLC(Programmable Logic Controller), and actuator. The sequential control of machine generally controlled by a PLC. The main fault occured at PLC in 3 control parts. In LC faults, operational fault is charged over 70%. This paper describes diagnosis model and data processing for remote monitoring and diagnosis system in machine tools with open architecture controller. Two diagnostic models based on the ladder diagram. Logical Diagnosis Model(LDM), Sequential Diagnosis Model(SDM), are proposed. Data processing structure is proposed ST(Structured Text) based on IEC1131-3. The faults from CNC are received message form open architecture controller and faults from PLC are gathered by sequential data.. To do this, CNC and PLC's logical and sequential data is constructed database.

• Acta Via Serica
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• v.2 no.2
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• pp.69-88
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• 2017

Since the beginning of the human world, man has tried to prove his presence on the earth. Wherever he moved, he left his marks in different forms. Whether he lived in caves, in open spaces or in-built structures, he left evidence in art form, the earliest of which are the cave paintings found in various regions of the world. These transformed into open spaces where man carved and painted images and writings on rock faces and boulders. Although Pakistan provided an early home to such art forms, they have been discovered in Kashmir for the first time and will be revealed in this paper. In the present survey, a great number of rock art sites were found and documented in detail. These rock art sites display the earliest communities who settled down or traveled through the region, highlighting their thoughts, beliefs and practices. The tentative chronology of these rock art sites ranges from Neolithic to Hindu periods, creating an interesting mosaic in the historic profile of Kashmir.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.61-70
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• 2014

The government supports the various systems on the premise of life-long education for improving the qualification of its people and supporting the lifelong career system. These systems help the educational activities for every generation from the teens. Each government department supports the learning activities for those who are related. In addition, each government department systemizes the regular education for advancing the performance of civil servant, by obliging a self-directed system to their member as well as by reflecting this educational activities in a promotion. This style of learning is provided not only offline but also online. However, not all necessary educational contents is furnished within the department. It is sometimes necessary to cooperate with the commissioned education and a professional educational institution. This thesis suggests three model systems while comparing one another. This paper suggests three system model. The first model is e-contents open place. The second model is e-contents open place. Finally, the suggest model is mixed form.

• Journal of computational fluids engineering
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• v.19 no.1
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• pp.15-20
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• 2014

Accurate simulation of free-surface wave flows around a ship is very important for better hull-form design. In this paper, a computational fluid dynamics (CFD) code, termed SNUFOAM, which is based on the open source libraries, OpenFOAM, was developed to predict the wave patterns around a ship. Additional anti-diffusion source term for minimizing a numerical diffusion, which was caused by convection differencing scheme, was considered in the volume-fraction transport equation. The influence of the anti-diffusion source term was tested by applying it to free-surface wave flow around the Wigley model ship. In results, the band width of the volume fraction contours between 0.1 to 0.9 at the hull surface was narrowed by considering the anti-diffusion term.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.1
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• pp.10-16
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• 2009

Modal characteristics of a cracked beam with a concentrated mass undergoing rotational motion are investigated in this paper. Hybrid deformation variables are employed to derive the equations of motion of a rotating cantilever beam. The flexibility due to crack, which is assumed to be open during the vibration, is calculated basing on a fracture mechanics theory. To obtain more general information, the equations of motion are transformed into a dimensionless form in which dimensionless parameters are identified. The effects of the dimensionless parameters related to the angular speed, the depth and location of a crack and the size and location of a concentrated mass on the modal characteristics of the beam are investigated numerically.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.47-52
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• 1996

The interpolator is very important in CNC machines. This study proposed a parametric curve interpolator(PCI) which can be used for machining any sculptured surface represented in a parametric form and generates commands for tool motion between CAD data points according to given accuracy demands. The proposed interpolator is superior to the existing linear interpolator in accuracy, feed rate and acceleration continuity. Moreover in comparison to the recently developed cubic spline interpolator, the PCI has the capability of handling higher order parametric curves and also ensures precise tracking in the velocity domain. Results from real time simulations and experiments on open architecture CNC machines equipped with the proposed interpolator are presented to show its practical capagility. It is believed that the combination of the proposed interpolator and the open architecture machine controller further advances the area of command generation which is an important aspect of CAD/CAM.

• International Journal of Ocean System Engineering
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• v.3 no.2
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• pp.77-89
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• 2013

The propeller performance has been investigated using a benchmark Duisburg Test Case ship with RANSE. First, the hydrodynamic characteristics of propeller in case of open water have been analyzed by a commercial CFD program and the results are compared with those of experimental data. Later, the flow around the bare hull has been solved and the frictional resistance value and form factor of the ship have been obtained and compared with those of ITTC57 formulation and experimental results for validation. The free surface effect has been ignored. A good agreement has been obtained between the results of RANSE and experiments at both stages. Then the ship - propeller interaction problem was solved by RANSE and the differences in thrust, torque and efficiency of propeller as compared with the open-water numerical results have been discussed.