• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.4
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• pp.207-215
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• 2009

In recent digital communication systems, the performance of Turbo Code used as the error correction coding method depends on the interleaver size influencing the free distance determination and iterative decoding algorithms of the turbo decoder. However, some iterations are needed to get a better performance, but these processes require large time delay. Recently, methods of reducing the number of iteration have been studied without degrading original performance. In this paper, the new method combining ME (Mean Estimate) stopping criterion with SDR (sign difference ratio) stopping criterion of previous stopping criteria is proposed, and the fact of compensating each method's missed detection is verified Faster decoding realizes that reducing the number of iterative decoding about 1~2 times by adopting our proposed method into serially concatenation of both decoder. System Environments were assumed DS-CDMA forward link system with intense MAI (multiple access interference).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.424-429
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• 2003

As a critical member of cable-stayed bridges, stay cables play an important role of supporting the entire structure. Traffic, wind or rain-wind induced vibrations of stay cables would be a major cause of degrading both safety and serviceability of the bridge. One of the effective alternatives to solve this problem is to employ the cable dampers. In order to design the cable damper optimally. it is necessary to exactly estimate the dynamic characteristics of the existing cables. Therefore, in this study, a cable exciting system (exciter) controlled digitally was developed. And to evaluate the performance of the cable exciter developed, a solution of the differential equation of cable motion considering the exciter was derived. Using the cable exciter. sine sweeping and resonance tests on a cable model were carried out to obtain the dynamic characteristics effectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.223-226
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• 2005

The purpose of this study is to discuss how strength and ductility of each system in low-rise R/C buildings combined with extremely brittle, shear and flexural failure systems have influence on seismic capacities of the overall system, which is based on seismic response analysis of SDOF structural systems. To simulate the triple lateral-load resisting system, structures are idealized as a parallel combination of two modified origin-oriented hysteretic models and degrading trilinear hysteretic model that fail primarily in extremely brittle, shear and flexure, respectively. Stiffness properties of three models are varied in terms of story shear coefficients, and structures are subjected to two ground motion components. By analyzing these systems, interaction curves of required strengths of the triple systems for various levels of ductility factors are finally derived for practical purposes.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.824-833
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• 2012

In this paper, a coordinated state-of-charge (SOC) control strategy for the energy storage system (ESS) operating under microgrid islanded mode to stabilize the frequency and voltage was proposed. The proposed SOC control loop is made up of PI controller, which uses a SOC state of the energy storage system as an input and an auxiliary reference value of secondary control as an output. The SOC controller changes the auxiliary reference value of secondary control to charge or discharge the ESS. To verify the proposed control strategy, PSCAD/EMTDC simulation study was performed. The simulation results show that the SOC of the ESS can be regulated at the desired operating range without degrading the stabilizing control performance by proposed coordinated SOC control method.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1650-1657
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• 2017

In this study, the distributed secondary voltage control of islanded microgrids with multi-agent consensus algorithm is investigated. As an alternative to a time-triggered approach, an event-triggered scheme is proposed to reduce the communication load among inverter-based distributed generators (DGs). The proposed aperiodic control scheme reduced unnecessary utilization of limited network bandwidth without degrading control performance. By properly establishing a distributed triggering condition in DG local controller, each inverter is only required to send voltage information when its own event occurs. The compensation of voltage amplitude deviation can be realized, and redundant data exchange related to fixed high sampling rate can be avoided. Therefore, an efficient use of communication infrastructure can be realized, particularly when the system is operating in steady state. The effectiveness of the proposed scheme is verified by simulations on a microgrid test system.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.665-670
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• 2016

This study deals with the possible degradation of toluene and acetic acid when subjected to cell-free enzyme system from the toluene degrading bacteria Pseudomonas putida and acetic acid degrading bacteria Cupriavidus necator. P. putida produces toluene dioxygenase only under the existence of toluene in culture medium and toluene is degraded to cis-toluene dihydrodiol by this enzyme. C. necator produces acetyl coenzyme A synthetase-1 and converts acetic acid to acetyl CoA in order to synthesize ATP to need for growth or PHA which is biodegradable polymer. In case of toluene degradation, the experiment was conducted before and after production of toluene dioxygenase as this enzyme, produced by P. putida, is an inducible enzyme. Toluene was detected using gas chromatography (GC). Similar amount of toluene was found in control group and before production of toluene dioxygenase (experimental group 1). However, reduction in toluene was detected after the production of toluene dioxygenase (experimental group 2). Acetic acid was detected through application of gas chromatography-mass spectrometer (GC-MS). The results showed the acetic acid peak was not detected in the experimental group to apply cell-free enzyme system. These results show that the cell-free enzyme system obtained from P. putida and C. necator retained the ability to degrade toluene and acetic acid. However, P. putida needs to produce the inducible enzyme before preparation of the cell-free enzyme system.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.211-224
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• 2008

Occurrences of large-scale food-related mishaps around the globe are degrading the safety and confidence on food items. This can be said to result from problems such as information asymmetry between the supplier and the consumer(information user). It makes it difficult to confirm product-related information including who produced an item how, what manufacturing process was involved, and how the product was distributed, and deal with a food-related trouble. The research verified and analyzed what has an effect on the intention to use Traceability System when the user uses information service.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.81-86
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• 2019

According to the needs of many users, motor pumps have been steadily developed and widely used in many industries where fluids are used. Motor pumps are used in a variety of environments, degrading quality and performance. It is becoming important to monitor the condition of motor pumps in order to maintain system performance and increase efficiency. This paper presents the method for effectively monitoring the condition of motor pumps. The designed MMI controller receives the collected data through data logging and output and controls the motor pump with touch screen. Implementing a Wi-Fi monitoring system and SCADA monitoring system based on Ethernet and RS485, user can monitor even if the user is far from the MMI controller without time and space limitation. In addition, by implementing a voice output system, the user can immediately recognize the situation through the sound. Therefore, through the proposed method, multi-monitoring system solves the cause of breakdowns and degradation of motor-pump and gives the possibility of commercialization by providing the convenience of maintenance to users.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.799-804
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• 2004

Dynamic characteristic of CD/DVD deck for vehicle is analyzed in this paper. Generally CD/DVD deck for vehicle is used from inferior environment with the vibration of the vehicle and shock of outside and so on. Therefore it must have the structure which is stabilized from the vibration to prevent read error. For this purpose, vibration characteristic of the deck for vehicle should be identified. To analyze characteristic of the deck system, we perform the signal analysis and modal testing using the FFT analyzer. Also we change the design factor degrading the performance of the deck system and verify the efficiency improvement using the acceleration measurement occurring to the sound discontinuation.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.128-137
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• 2003

Continuously variable damper can yield diverse damping forces for a single damping velocity. It is widely used in the semi-active suspension system since, with right control logics, it can enhance ride comfort compared to the passive damper while not degrading driving safety. A key to the successful design of the continuously variable damper is the knowledge of its complex and nonlinear characteristics. In this paper, research has been done for analyzing characteristics of the continuously variable damper. Various damper components have been investigated and their effects upon the force-velocity characteristics of the damper have been examined. The effects of the damper characteristics change upon ride comfort and driving safety have also been investigated by numerical simulations.