• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.11 no.2
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• pp.75-79
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• 2005

With three kinds of agricultural products such as perilla leaves, this research is focussed on how to keep a freshness of agricultural products during long time transport by sea. In case of export fresh agricultural products by sea, research on products loading method onto the pallet is very important factor for keeping effective cold air circulation inside the freezing marine container. Details are as follows: Clear examination of palletization for cold air ventilation inside the container. Optimization of package dimension for best loading efficiency onto the standard pallet. Best layout of palletized products inside the container. Research for the change of circumstance and product quality inside the pack.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.4
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• pp.7-15
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• 2002

It is of critical importance to understand the characteristics of papermaking additives and their reaction mechanisms to fully utilize the benefits they provide. Among the papermaking additives, retention aids play critical roles in improving productivity, product quality and process economy. Diverse research efforts to understand the reaction mechanisms between cationic polymers and anionic microparticles have been made since microparticle retention systems were introduced into the market. And it is most commonly accepted that flocs formed by the addition of cationic polymers are dispersed by shear force and the broken flocs are reflocculated instantly with the addition of microparticles. There are still many unanswered questions, however, on the reaction phenomena between cationic polymers and anionic microparticles. In this study, several cationic polymers including waxy maize starch, com starch and guar gum were used to investigate their retention efficiency when they were used along with anionic colloidal silica.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.13.1-13.1
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• 2011

Photoelectrochemical solar cells such as dye-sensitized cells (DSSCs), which exhibit high performance and are cost-effective, provide an alternative to conventional p-n junction photovoltaic devices. However, the efficiency of such cells plateaus at 11~12%, in contrast to their theoretical value of 33%. The majority of research has focused on improving energy conversion efficiency of DSSC by controlling nanostructure and exploiting new materials in photoelectrode consisting of semiconducting oxide nanoparticles and a transparent conducting oxide electrode (TCO) [1-5]. In this presentation, we introduce inverse opal-based scattering layers containing highly crystalline anatase nanoparticles and their feasibility for use as bi-functional light scattering layer is discussed in terms of optical reflectance and charge generation properties as a function of optical wavelength. A new ITO nanowire-based photoelecrode is also introduced and its unique charge collection property is presented, demonstrating potential use for highly efficient charge collection in DSSC.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.187-192
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• 2010

Korean railway has run about 110 years since 1989 and played a great role of industrialization in Korea. It is known that rail transport systems have many advantages of being more safe, energy-efficient, and environment-friendly, as compared to other transportation systems. However, railway incidents are often attributed to the failure of safety management and critical to the efficiency of railroad industry. This study reviewed economic, financial, and general statistical information on Korea Railroad. Based on the statistical data, the effect of accidents on railroad management was analyzed. Correlation analysis revealed that railway accident had a negative effect on the gross profit of Korea Railroad. In order to reduce potential risks and incident rate, some recommendations are proposed. Actual or potential applications of this research include safety guidelines for improving efficiency of railroad industry.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.12
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• pp.82-87
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• 2007

Excavator has been used in wide field since the attachment in the end effect can be changeable according to the purpose of working. However, efficiency of work using excavator mainly depends on an operator's ability. For the purpose of improving the efficiency of work and reducing the fatigue of operator, the automatic excavator system has been researched. In this paper, the tracking control system of each links of excavator is designed before developing the automatic excavator system. In order to apply the tracking control system, the pneumatic excavator system is developed and the tracking control system is applied. For designing the tracking control system, the adaptive sliding mode control algorithm is proposed. The performance of the proposed control system is evaluated through experiments using the pneumatic excavator system.

• Proceedings of the Korean Association for Survey Research Conference
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• 2003.06a
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• pp.19-28
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• 2003

Weighting adjustment is a method of improving the efficiency of the estimator by incorporating auxiliary variables at the estimation stage. One commonly used method of weighting adjustment is the poststratification, which is a special case of regression estimation but is relatively feasible in terms of actual implementation. If too many auxiliary variables are used in the poststratification, the bias of the resulting point estimator is no longer negligible and the final weights may have extreme weights. In this study, we propose a method of weight ing adjustment that compromises the efficiency and the bias of the point estimator. A limited simulation study is also presented.

• Journal of the Korea Safety Management & Science
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• v.9 no.3
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• pp.135-142
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• 2007

The authors used association rules and patterns in sequential of data mining in order to raise the efficiency of engineering changes. The association rule can reduce the number of engineering changes since it can estimate the parts to be changed. The patterns in sequential can perform engineering changes effectively by estimating the parts to be changed from sequence estimation. According to this result, unnecessary engineering changes are eliminated and the number of engineering changes decrease. This method can be used for improving design quality and productivity in company managing engineering changes and related information.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.5-10
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• 2013

Diesel engines have the advantages of good fuel efficiency and low emissions. Therefore, car makers have been developed various kinds of diesel engine management system to clean up emissions while improving fuel efficiency. One of them is the common rail system. In the common rail system, diesel fuel is injected into the combustion chamber at ultra high pressures up to 1,800 bar to ensure more complete combustion for cleaner exhaust gas, and highly precise multiple injection reduces NOx emission, combustion noise and vibration. Generally speaking, common rail system consists of booster pump, high pressure pump, common rail, injectors, control valves, and sensors. The high pressure pump receives low pressure fuel from the booster pump and supply high pressure fuel to injectors through the high pressure common injection rail. Therefore, high pressure pump has an important role in common rail system. In this paper, we have investigated the performance of high pressure pump of common rail system.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.689-691
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• 1992

In this study, slip frequency control for a single-sided linear induction motor(SLIM) is discussed. We adopted variable slip frequency pattern in stead of constant slip frequency pattern under V/f constant mode, which is effective in improving driving efficiency of SLIM. And the dynamic characteristics are analyzed by using equivalent circuit during the accelerating time.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1865-1874
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• 2011

This paper proposes a novel maximum power point tracking(MPPT) using a new fuzzy control(NFC) algorithm for robust in insolation variation. Maximum power point(MPP) of solar cell has to achieve for improving output efficiency because it is changed with insolation and temperature. Conventional MPPT controller such as constant voltage(CV), perturbation and observation(PO) and incremental conductance(IC) are researched. But these controller have the problem that is failure to MPP with environment changing. The proposed NFC controller is based the fuzzy control algorithm and able to robust control with environment changing. Also the proposed controller of PV system is modeled by PSIM and the response characteristics according to the parameter variation is compared and analyzed. The validity of this controller is proved through response results.