• 사회경제평론
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• v.31 no.2
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• pp.105-126
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• 2018

In this paper, I makes some critical comments on the temporal single-system interpretation (TSSI) of Marxian value theory. The first concerns the claim that the Fundamental Marxian Theorem (FMT) holds within the TSSI under completely general conditions. Based on the idea that the nominal profit does not well fit the FMT, the TSSI proponents suggest that more relevant for proving the TSSI FMT is the real profit, defined by deflating the output prices. In contrast, I propose a more general approach where three possible concepts of profit are all considered, in which case the result is that whether the FMT holds within the TSSI is indeterminate. Second, the refutation of the Okishio theorem presented in Kliman (1996) is critically examined, focusing on the criticism raised in the literature that the Kliman model ignores the cost-reduction criterion as for the technical change and therefore cannot be considered as an internal refutation of the Okishio theorem. Drawing upon the criticism, I explicitly incorporate the cost-reduction criterion into the Kliman model and show that the continuous labor-saving technical change of the Kliman model is not necessarily cost-reducing and under certain conditions is cost-neutral or cost-raising.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.389-393
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• 2003

This paper describes the design of enhanced TSSI RF Power Detector which has wide dynamic range using switch and Log amp. This Power Detector consists of low and high gain loops, and they adaptively switched by output DC voltage which is proportioned to input power level. Because Power Detector needs to separate the channel, so architecture is heterodyne system having 70MHz intermediate frequency. This proposed RF Power Detector is settle to the satisfaction of Closed loop power control system for W-CDMA optic repeater, and the obtained dynamic range cover the higher than 50dB.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1791-1801
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• 2016

This paper considers a carrier based signal injection method for use in the three shunt sensing inverter (TSSI) for sensorless motor control. It also analyzes the loss according to the injection axis of the voltage signal. To remove both the phase current and rotor position sensors, a sensorless method and a phase current reconstruction method can be simultaneously considered. However, an interaction between the two methods can be incurred when both methods inject voltage signals simultaneously. In this paper, a signal injection based sensorless method with the 120° OFF Discontinuous PWM (DPWM) is implemented in a TSSI to avoid this interaction problem. Since one leg does not have a switching event for one sampling period in the 120° OFF DPWM, the switching loss is altered according to the injection axis. The switching loss in the d-axis injection case can be up to 32% larger than that in the q-axis injection case. Other losses according to the injection axis are also analyzed.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.2
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• pp.175-180
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• 2017

The measurement of three-phase current is important to control the instantaneous torque of a interior permanent magnet synchronous motor(IPMSM) using a three-phase inverter. Therefore, shunt resistors are used in low-cost motor-driving systems to measure three-phase current instead of additional current sensors that are too expensive for these systems. However, in certain regions of a space vector plane, shunt resistors cannot reconstruct three-phase current in high-speed driving mode. In this paper, predictive current control is used to compensate for the three-phase current in those regions, which results in a reduction of current ripple in a three-shunt sensing inverter(TSSI) and torque ripple in IPMSM.

• Environmental Engineering Research
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• v.21 no.2
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• pp.152-163
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• 2016

Present study investigates the potential of cassava peel and rubber tree bark for the removal of Cr (VI) from aqueous solution. Removal efficiency of more than 99% was obtained during the kinetic adsorption experiments with dosage of 3.5 g/L for cassava peel and 8 g/L for rubber tree bark. By comparing popular isotherm models and kinetic models for evaluating the kinetics of mass transfer, it was observed that Redlich-Peterson model and Langmuir model fitted well ($R^2$ > 0.99) resulting in maximum adsorption capacity as 79.37 mg/g and 43.86 mg/g for cassava peel and rubber tree bark respectively. Validation of pseudo-second order model and Elovich model indicated the possibility of chemisorption being the rate limiting step. The multi-linearity in the diffusion model was further addressed using multi-sites models (two-site series interface (TSSI) and two-site parallel interface (TSPI) models). Considering the influence of interface properties on the kinetic nature of sorption, TSSI model resulted in low mass transfer rate (5% for cassava peel and 10% for rubber tree bark) compared to TSPI model. The study highlights the employability of two-site sorption model for simultaneous representation of different stages of kinetic sorption for finding the rate-limiting process, compared to the separate equilibrium and kinetic modeling attempts.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.99-100
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• 2016

In a AC motor used by three phase inverter, the phase current must be measured to control instantaneous torque. It is expensive to use current sensor for measuring current in low cost motor. So, shunt resistor is used to measure current. But, the method sensing the phase current using shunt resistor cannot perform the vector control in high speed because of the area that impossible to restore three phase current. In this paper, predictive current is proposed for reconstructing the current in the impossible current sensing area that reduce the current ripple in TSSI(Three shunt sensing inverter) for PMSM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.12
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• pp.1300-1312
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• 1991

In this paper we syudy the time slot sequence integrity(TSSI) of multi-slot calls in the single-buffered switching networks and analyze their traffic characteristics in terms of traffic mixture ratio, number of random searches for idle time slots, and their blocking probablities. This result can be utilized in the design of wideband switching networks in the single buffered systems, such as TDX IA/B swithcing systems, for accommodating multi slot calls.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.224-225
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• 2016

매입형 영구자석 전동기에 가격과 부피를 줄이기 위해 3개의 션트 저항을 이용하는 인버터를 사용하였고 회전자 위치센서를 제거하기 위해 모델기반 센서리스 기법을 사용하였다. TSSI (Three Shunt current Sensing Inverter)의 문제점인 특정 전압 이상에서는 전류를 검출할 수 없는 영역이 생기게 된다. 이를 예측전류를 사용하여 전류복원 불가영역을 개선하였다.