• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.218-223
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• 1993

In this paper, we present a full digital control scheme which controls currents and speed of the permanent magnet AC servo motor with large range of bandwidth and high performance. The current equations of the permanent magnet AC servo motor are linearized by feedback linearization technique. Both acceleration feedforward terms and IP controllers, whose gains are functions of motor speed, are used in order to control motor currents. In addition the phase delays in current control loops are compensated by placing phase lead-lag compensators after current commands, which make it possible to avoid high gains in the current controllers. Unity power factor can be achieved by the proposed current controller. Pulsewidth modulation is performed by way of the well-known comparison with a triangular carrier signals. The velocity controller is designed on the basis of the linearized model of the permanent magnet AC servo motor by the proposed current controller. The performance of the entire control system is analyzed in the presence of uncertainty in the motor parameters. The proposed control scheme is implemented using the digital signal processor-based controller composed of an Analog Device ADSP 2111 and a NEC78310. The pulsewidth modulation (PWM) signals are generated through a custom IC, SAMSUNG-PWM1, which has the outputs of current controllers as input. The experimental results show that the permanent magnet AC servo motor can be always driven with high dynamic performance by the proposed full digital control scheme of motor speed and motor current.

• Journal of Technology Innovation
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• v.19 no.1
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• pp.1-27
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• 2011

This paper aims to measure and analyze R&D productivities and efficiencies of 17 major OECD countries including Korea over the 1984-2008 period by using the Malmquist Productivity Index and Data Envelopment Analysis, classifying R&D performance into an output and outcome aspects. It also searches the Korea's current status and characteristics in each R&D stage to enhance Total Factor Productivity (TFP) compared with other developed countries. Our major findings are the followings: (i) Korea's productivity index of R&D input vis-a-vis R&D output is very high (13.39% annual growth rate) compared with those of major advanced countries, whereas the annual average of efficiency index is very low (0.33), i.e. Korea's technical efficiency index has risen to 0.83 at the last time series started at 0.10 point and come up to the level of major advanced countries. (ii) the Korea's productivity index of R&D output vis-a-vis R&D outcome is very low (14.02% annual reduction rate) compared with those of major advanced countries, whereas the annual average of efficiency index is very high (0.22), i.e. Korea's integrated frontier technical efficiency index has dropped to 0.057 at the last time series started at 1.00 point and coming up to the level of major advanced countries. (iii) The productivity of R&D input vis-a-vis R&D outcome is positively correlated with that of R&D output vis-a-vis R&D outcome and the growth of R&D input factors. In a nutshell, it implicates that the effort to take advantage of R&D outputs, namely establishing the diffusion and commercialization system of technical knowledge to the level of developed countries, should be strengthened over that on the growth of R&D investment and output for enhancing R&D productivity and efficiency in Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.6
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• pp.1431-1438
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• 2015

According to the report from OECD, 80% of world trade quantity was influenced by standard, 50% of EU trade demand certification of forced standard. This leads to develop standard connected with R&D in most country and company worldwide. Recently, Technical standards have advantage of reduction of production cost and market dominating power. Standardization of construction technology has very important role that ouput of R&D refer to KS, national construction standards and it activates in the market. However, domestic construction research related to effectiveness of standadization fall short of expectation in comparison with manufacturing industry. This study present criteria that can analyze the performance and effectiveness in construction R&D project connected with standardization. And it applied domestic R&D cases (finished from 2000 to 2009), analyzes ouput of standadization and economic effect to verify the value of construcion technology standardization.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.6
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• pp.629-637
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• 2021

For the stabilization of laser output power and wavelength of the high power fiber laser, the cooling plate must be properly taken into account. In this study, three analyzing methods which are heat transfer theory, CFD and experiment are used to analyze cooling plate performance by measuring pump Laser Diode(LD) temperature. Under limited operating conditions of a cooling plate, the internal flow of cooling plate is transitional flow so that the internal flow is assumed to be laminar and turbulence flow and conducted theoretical calculation. Through CFD, temperature of pump LD and characteristics of the internal flow were analyzed. By the experiment, temperature of pump LD was measured in real conditions and the performance of the cooling plate was verified. The results of this study indicate that three analyzing methods are practically useful to design the cooling plate for the high power fiber laser or similar things.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.39-42
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• 2006

There are various analysis functions(including prediction of path loss, analyzing of capacity and coverage, etc.) of simulation tool to design and optimize the mobile communication network. Its reliability absolutely effects the performance of mobile communication network. Especially as the wireless network highly advancing focused on data service, it more needs to research and develop on the standard establishment of reliability of the simulation tool. Also it is important the systematic research how to improve the reliability of simulation tool. In this paper, to give the concrete process and skill about how to improve reliability, we define the kinds of reliability at first. And then we explain the comparison results between real field measurement data and theoretic simulation data.

• Journal of Korea Technology Innovation Society
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• v.3 no.1
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• pp.139-153
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• 2000

The aim of this paper is to provide a new model to evaluate the quantitative value of technology(nonfinancial benefits). This new model is based on the technology stock(technology level) ac-quired in R&D process. The model can explain the quantitative relation between the technology stock(level) and the market value of technology as considering the R&D expenditure to acquire technologies above a certain level(>70%) in comparison with the advanced country and the cost to prevent the technology obsolescence. The value of non-destructive testing technology which is one of the electric power technology is measured quantitatively as a case study.

• Journal of Positioning, Navigation, and Timing
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• v.3 no.2
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• pp.53-62
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• 2014

In the guided missile and unmanned vehicle system, the navigation system is one of the most important components. Recently, low-cost effective smart projectiles and guided bomb are being developed using MEMS based navigation system which has high-G, low-cost and small size. In this paper, locally developed MEMS based GPS/INS integrated navigation system will be introduced in comparison with the state of the art of MEMS based navigation system. And technical design and development method is described to satisfy the required performance of GPS receiver, MEMS inertial sensor assembly, navigation computer and software.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.113-119
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• 2012

CTBA(Coupled Torsion Beam Axle) has been adapted as the rear suspension of a compact car. Because that has the advantage of cost and weight in comparison with multi-link type. But CTBA has the disadvantage in vehicle stability to become oversteer occurring toe-out of the rear wheel when cornering and braking. In this study, we suggested CTBA Geometry Compensation System to overcome the disadvantage of CTBA. We predicted braking and cornering vehicle performance from proposed equation and numerical simulation. And also, the results were compared to objective and subjective evaluation in vehicle.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.515-521
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• 2019

The C-ITS requires the lane level positioning of the vehicle in the land transportation environment, and it is most effective to utilize the global navigation satellite system. In the precision positioning system based on satellite navigation, the evaluation of dynamic environment of lane level positioning performance should be accompanied and the evaluation system configuration should be preceded. In addition, performance analysis must be performed according to various environments that change according to traffic or road conditions in a dynamic environment. In this paper, we describe with the performance of traffic and road environment through the evaluation system of lane positioning precision positioning user system based on satellite navigation system. The numerical performance evaluation was carried out based on the data collected by carrying out the actual driving. The performance evaluation by the actual driving trajectory and driving image comparison was performed to derive and analyse evaluation results of positioning performance according to driving condition.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.3
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• pp.22-29
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• 2013

In recent years, the construction of high-rise buildings are promoted. According to these, there are many needs about new technologies to strengthen the building performance and high-strength steel is regarded as one of these for promoting building performance. In Korea, high-strength steels which stress are over 600MPa are on market and in aborad, super high-strength steels over 1000MPa are developing and they expected to promote the building performance. But there are still doubts about applying high-strength steel members because of size effect and worry of brittle fracture. In this reports, we propose results of performance and analysis tests for use with general steel. We propose the characteristic of high-strength steels first and next the results of performance test to show they satisfy the performance that designers expect. And last, we compare the results of test and analysis for acquire the alanysis reliability in non-linear analysis with high-strength steels.