• Journal of the Korean Society for Precision Engineering
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• v.9 no.1
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• pp.126-136
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• 1992

In this paper, a simple structured feedback compensation scheme for a electro-hydraulic servo system to keep the response characteristics unchanged regardless of the load variation is proposed. In electro-hydraulic servo system, servovalve is most important control element. But the relation between input corrent and output flowrate of the servovalve has properties as follows; firstly, in spite of constant input current, output flowrate decreases as load pressure increases, secondly, according to frequency response of typical servovalve, the characteristics of gain and phase shift is something like 2'nd order system. Load pressure feedback compensation method has been applied to eliminate the first influence, the second influence has been improved by phase lead compensation method. As a result of above compensation methods, regardless of variation load condition, spring and inertia load, the compensation scheme has been verified to be effective within the range of frequency less than 25Hz by static response and dynamic response in time domain and frequency domain through experiments.

• Journal of Agricultural Extension & Community Development
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• v.18 no.3
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• pp.351-384
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• 2011

The purpose of this study is to look at the case of the German compensation system for farmers' accidents and to build a basic scheme in our country's compensation system for farmers' accidents. When you view examples of Germany, the social insurance scheme for farmers accidents in korea should be design as an independent institution from the existing industrial accident insurance, and it comes to relationships with other social insurance system, preferably with complementary personalities. A general rule of the compensation system applies to all farmers in principle but the coverage limits part-time farmers. Financial burden consists of the mix of insurance premium and state aid. The type and level of benefits is similar to the current industrial accident insurance, which give priority to places on economic security for keeping farmworks, such as cost for using temporary farmers, rather than income loss. In terms of financial system, pay-as-you-go system would be better because of immediate payment with the introduction of the compensation system. The compensation system might be managed and administrated by the existing nationwide organization. Of course, for operating of system review and further research on the technical details such as premium issues and funding problems of government support, the exact classification of the target coverage, premiums based on estimated income for the farmers' estimation, the exact statistical data on the accumulation of agricultural disaster is needed.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.492-495
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• 1997

Integral type system is that a system is represented by a proper rational function. In this paper, novel control scheme based on model reference approach is proposed for integral type system. The proposed scheme compensates various undesirable effects of the system. In especially, the proposed scheme applied to DC servo control system, analyzed its control characteristic. Performances of the proposed system show excellent control characteristics; complete compensation of the undesirable nonlinear friction and load viscous, For proving realistic validities, LOS(Line Of Sight) stabilization system which has typically many nonlinear effects is experimented. After executing the computer simulation in "MATLAB", then the results are compared with the experiments. The results are very similar in theoretical study and the proposed control scheme is successfully verified. verified.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.1
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• pp.45-48
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• 2010

An inter-pin skew compensation scheme is proposed, which minimizes the inter-pin skew of parallel interface induced by unequal trace length and loading of printed circuit board (PCB). The proposed scheme measures the inter-pin skew and compensates during power-up with simple hardware. The proposed scheme is applied to 3.2-Gb/s/pin DDR4 SDRAM and implemented in a 0.18 m CMOS process. The inter-pin skew is compensated in 324-cycles of 400-MHz clock and the skew is compensated to be less than 24-ps.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.2
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• pp.97-111
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• 1995

In this paper, we investigate path compensation scheme for the machining errors due to tool deflection in 2D contour machining. The significance of the deflection error is first shown by experiments, and a direct compensation scheme is sought. In the presented scheme, the tool path is evaluated and correcte based on the instantaneous deflection force model, until the desired contour can be obtained under the presence of tool deflection in actual machining. In the sense that the developed method estimates and compensates the machining errors via modifying the tool path, it is distinguished from the previous approach based on geometric simulation and cutting simulation. Further, it can be viewed as a direct and active method toward direct shape control in CNC machining. Simulation results are included to show the validity and adequacy of the path-modification scheme under various cutting conditions.

• Journal of Power Electronics
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• v.11 no.4
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• pp.576-582
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• 2011

This paper presents a novel control strategy for selective compensation of power quality (PQ) problems, depending upon the limited rating of voltage source inverters (VSIs), through a unified power quality conditioner (UPQC) in a three-phase four-wire distribution system. The UPQC is realized by the integration of series and shunt active power filters (APFs) sharing a common dc bus capacitor. The shunt APF is realized using a three-phase, four-leg voltage source inverter (VSI), while a three-leg VSI is employed for the series APF of the three-phase four-wire UPQC. The proposed control scheme for the shunt APF, decomposes the load current into harmonic components generated by consumer and distorted utility. In addition to this, the positive and negative sequence fundamental frequency active components, the reactive components and harmonic components of load currents are decomposed in synchronous reference frame (SRF). The control scheme of the shunt APF performs with priority based schemes, which respects the limited rating of the VSI. For voltage harmonic mitigation, a control scheme based on SRF theory is employed for the series APF of the UPQC. The performance of the proposed control scheme of the UPQC is validated through simulations using MATLAB software with its Simulink and Power System Block set toolboxes.

• The Korean Society of Law and Medicine
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• v.7 no.2
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• pp.271-310
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• 2006

In the situation of bringing out of social problem about the medical accident and medical dispute, from 1988 the enactment activity for a legislative bill on conciliation of dispute has promoted, a legislative bill on prevention and relief of medical accident was again proposed in December, 2005. This bill has been faced rough going in review process of National Assembly. Because the purpose of this legislative bill is the conciliation of interest of between medical service consumer and medical service supplier, an item of issues of law is no-fault compensation scheme. However, as no-fault compensation scheme runs counter to the principle liability with fault in our civil law, as expected, whether the inducement is valid or, if induced, the problem is not must be totally reviewed. First of all, the general of principle liability without fault and especially the medical system in foreign countries are reviewed, by reviewing an issue and the pros and cons of the inducement of no-fault compensation scheme, this article draws the conclusion. After all, considering that the necessity adapting Gefahrdungschftung in medical accident as much as other industrial fields exists, the many provisions of the principle liability without fault exists in civil law and special law of our law system, and no-fault compensation scheme let legislative purpose be, to what extent, achieved by conciliating patient and doctor, the inducement of principle liability without fault in medical field is reasonable in the aspect of politic and legal system.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.859-862
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• 1998

An offset compensation scheme for rail-to-rail CMOS op-amps with complementary input stages is presented. Two auxiliary amplifiers are used to compensate for the offsets of NMOS and PMOS differnetial input stages, and ping-pong control is employed for continuous-time operation. Simulation and measurements resutls show that offsets are reduced about 20 times by this scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9C
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• pp.905-912
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• 2007

This paper proposes an efficient estimation and compensation scheme of IQ imbalance for OFDM-based WLAN systems in the presence of symbol timing error. Since the conventional scheme assumes perfect time synchronization, the criterion of the scheme used to derive the estimation of IQ imbalance is inadequate in the presence of the symbol timing error and the system performance is seriously degraded. New criterion and compensation scheme considering the effect of symbol timing error are proposed. With the proposed scheme, the IQ imbalance can be almost perfectly eliminated in the presence of symbol timing error. The bit error rate performance of the proposed scheme is evaluated by the simulation. In case of 54 Mbps transmission mode in IEEE 802.11a system, the proposed scheme achieves a SNR gain of 4.3dB at $BER=2{\cdot}10^{-3}$. The proposed compensation algorithm of IQ imbalance is implemented using Verilog HDL and verified. The proposed IQ imbalance compensator is composed of 74K logic gates and 6K bits memory from the synthesis result using 0.18um CMOS technology.

• Safety and Health at Work
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• v.2 no.2
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• pp.148-157
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• 2011

Objectives: Although compensation for occupational injuries and diseases is guaranteed in almost all nations, countries vary greatly with respect to how they organize workers' compensation systems. In this paper, we focus on three aspects of workers' compensation insurance in Organization for Economic Cooperation and Development (OECD) countries - types of systems, employers' funding mechanisms, and coverage for injured workers - and their impacts on the actual frequencies of occupational injuries and diseases. Methods: We estimated a panel data fixed effect model with cross-country OECD and International Labor Organization data. We controlled for country fixed effects, relevant aggregate variables, and dummy variables representing the occupational accidents data source. Results: First, the use of a private insurance system is found to lower the occupational accidents. Second, the use of risk-based pricing for the payment of employer raises the occupational injuries and diseases. Finally, the wider the coverage of injured workers is, the less frequent the workplace accidents are. Conclusion: Private insurance system, fixed flat rate employers' funding mechanism, and higher coverage of compensation scheme are significantly and positively correlated with lower level of occupational accidents compared with the public insurance system, risk-based funding system, and lower coverage of compensation scheme.