• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.42-48
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• 2021

Zn and Al added LiNi0.85Co0.15O2 cathode materials were synthesized to improve electrochemical properties and thermal stability using a solid-state route. Crystal structure, particle size and surface shape of the synthesized cathode materials was measured using XRD (X-ray diffraction) and SEM (scanning electron microscopy). CV (cyclic voltammetry), first charge-discharge profiles, rate capability, and cycle life were measured using battery cycler (Maccor, series 4000). Strong binding energy of Al-O bond enhanced structure stability of cathode material. Electrochemical properties were improved by preventing cation mixing between Li+ and Ni2+. Large ion radius of Zn+ increased lattice parameter of NC cathode material, which meant unit-cell volume was expanded. NCZA25 showed 80% of capacity retention at 0.5 C-rate during 100 cycles, which was 12% higher than that of NC cathode. The discharge capacity of NCZA25 showed 104 mAh/g at 5 C-rate. NCZA25 achieved 36 mAh/g more capacity than that of NC cathod. NCZA25 cathode material showed excellent rate capability and cycling performance.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.2
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• pp.49-55
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• 1982

The purpose of this study is to classify the factors influenced on the damages of head works suffered from the storm flood occurred on July 22 1980 in both Musim and Bochong rivers and to find out an integral counter measures against the causes influenced on the disaster of head works in the engineering aspect of planning, design, construction and maintenance. In this survey, number of samples was taken 25 head Works, and the counter measures against the causes of their disasters summarized was as follows, 1. In the aspect of planning a. As the flood water level after the establishment of head works is more increased than the level before setting of head works owing to having more gentle slope of river bed between the head works than nature slope of river bed. Number of head works should be reduced for the appropriate annexation of them b. In the place where head works is established on the curved point of levee, the destruction of levee becomes severe by the strong deflective current. Therefore the setting of head works on the curved point should be kept off as long as possible and in case of unavoidable circumstances the construction method such as reinforced concrete wall or stone wall filed with concrete and anchored bank revetments should be considered. 2. In the aspect of design a. As scoring phenomena at up stream is serious around the weir Where the concentration of strong current is present in such a place, up stream apron having impermeability should be designed to resist and prevent scoring. b. As the length of apron and protected bed is too short to prevent scoring as down stream bed, the design length should be taken somewhat more than the calculated value, but in the case the calculated length becomes too long to be profitable, a device of water cushion should be considered. c. The structure of protected river bed should be improved to make stone mesh bags fixed to apron and to have vinyl mattress laid on river bed together with the improvement for increasing the stability of stone mesh bags and preventing the sucked sand from the river bed. d. As the shortage of cut-off length, especialy in case of the cutoffs conneting both shore sides of river makes the cause of destruction of embankment and weir body, the culculation of cut-off length should be taken enough length based on seepage length. 3. In the aspect of design and constructions a. The overturing destruction of weir by piping action was based on the jet water through cracks at the construction and expansion joints. therefore the expansion joint should be designed and constructed with the insertion of water proof plate and asphalt filling, and the construction joint, with concaved shape structure and steel reinforcement. b. As the wrong design and construction of the weep holes on apron will cause water piping and weir destruction, the design and construction of filter based on the rule of filter should be kept for weep holes. c. The wrong design and construction of bank revetment caused the severe destruction of levee and weir body resulting from scoring and impulse by strong current and formation of water route behind the revetment. Therefore bank revetment should be designod and constructed with stone wall filled with concrete and anchored, or reinforced concrete wall to prevent the formation of water flow route behind the wall and to resist against the scoring and impulse of strong stream. 4. In the aspect of maintenance When the damaged parts occurred at head works the authorities and farmers concerned should find and mend them as soon as possible with mutual cooperation, and on the other hand public citizen should be guided for good use of public property.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.730-742
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• 2014

In the case of On-demand routing protocol in cognitive radio ad-hoc networks, broadcasting of control packets may occur common control channel overload and packet collisions during the routing procedure. This situation is to increase the overhead of path finding and also limited to find the accurate and reliable path. Since reliable channel and path finding is restricted, path life time is shorten and path reliability is reduced. In this paper, we propose a new routing algorithm that reduces control channel overhead and increases path life time by considering the probability of appearance of primary user and channel status of neighbor nodes. Each node performs periodic local sensing to detect primary user signal and to derive primary user activity patterns. The probability of primary appearance on the current channel and the channel status can be obtained based on the periodic sensing. In addition, each node identifies the quality of the channel by message exchange through a common channel with neighbor nodes, then determines Link_Levels with neighbor nodes. In the proposed method, the Link Level condition reduces the number of control messages that are generated during the route discovery process. The proposed method can improve path life time by choosing a path through Path_Reliability in which stability and quality are weighted depending on the location. Through simulation, we show that our proposed algorithm reduces packet collisions and increases path life time in comparison with the traditional algorithm.

• Land and Housing Review
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• v.6 no.2
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• pp.61-66
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• 2015

This study is the realization of natural gas as ways to advance the South and the continental railway linking basic research was conducted on railway transport. Summary data on the Status of North Korean railway which was to have reviewed the case of LNG railway transportation in Japan and China is becoming an LNG tank containers by rail transportation is done. In the case of Korea, the stability of railway transportation through the development of LNG tank containers and rail transportation pilot project was tested. It was set up and the basic directions of freight trains transport routes and methods for rail transport 7.5 million tons of natural gas per year. TKR ~ TSR between the LNG transportation business is an existing railway south. North. Russia gas pipeline (PNG) instead of a separate project to replace the business SRX (Silk Road Express) is a symbolic project for the early realization of the Eurasian railway linking policy. This study may give greater meaning to secure the iconic railway transport route for continental transport of containers and bulk cargo (coal, ores, etc.).

• Journal of Pharmaceutical Investigation
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• v.41 no.2
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• pp.103-109
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• 2011

The objective of the study was to prepare self-microeulsifying drug delivery system (SMEDDS) incorporating atorvastatin calcium and evaluate its properties and oral bioavailability. Solubility of atorvastatin in various vehicles was determined. Pseudo-ternary phase diagrams were constructed to identify the good self-emulsification region. The droplet size distributions of the resultant emulsions were determined by dynamic light scattering measurement. The mean droplet size of chosen formulation (20% ethyl oleate, 40% tween-80, 40% Carbitol$^{(R)}$) was $23.4{\pm}1.3$ nm. The SMEDDS incorporating atorvastatin calcium appeared to be associated with better performance in dissolution and pharmacokinetic studies, compared with raw atorvastatin calcium. In dissolution test, the release percentage of atorvastatin from SMEDDS mixture could rapidly reach more than 95% within 3 min. Oral $AUC_{0{\rightarrow}8hr}$ values in SD rats was $1994{\pm}335\;ng{\cdot}hr/mL$, which significantly increased (P<0.05) compared with raw atorvastatin calcium. The SMEDDS formulation was relatively stable when stored at $4^{\circ}C$ during 3 months. Our studies illustrated the potential use of SMEDDS for the delivery of hydrophobic compounds, such as atorvastatin, by the oral route.

• International Commerce and Information Review
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• v.16 no.1
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• pp.145-161
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• 2014

The study has try to find out the relationship between airfreight service quality and satisfaction in international forwarding practice which has focused to figure out the mediating role of performance that measured as subjective evaluation on profit. For the purpose of this paper, questionnaire survey has been performed on the relationship among the procedure of the air freight service quality was found to have not only direct influence but also indirect impact through performance on satisfaction. This research made some contribution both academicals and logistic practices. Academically, it is the first research to address the relationship between air freight service quality and profit performance in Korean academic field. Practically, this study provides justification for the investment to improve forwarding service quality. The results of this study bear some implications on international shipping and practice. The quality of the air cargo transportation management system for customer satisfaction and its impact on business performance in the process to make an empirical identifies. The role and influence of the working-level analysis to derive the performance as transportation management, as well as the effectiveness of customer satisfaction for quality and promote a point. Arrange this point take advantage of air cargo companies are composed of service quality management system for the dimension of course aims to foster a competitive advantage in terms of performance. This paper suggest that real-time movement of the consignment route provides information such as verification and business cooperation for the purpose of proper features a reflecting on the stability of cargo air freight management system, that improve the quality of services on this performance to increase the customer satisfaction strategy in connected getting and so on, is in the process of the formation of customer satisfaction.

• Spatial Information Research
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• v.20 no.6
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• pp.33-43
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• 2012

As part of recent sustainable transport, bike has come into the spotlight as a green transport at close range to link between walking and public transit and also alterative to solve problems of existing vehicle travel. Some arguments on promotion of using bicycles have already been made in Europe, the U.S and other developed countries. To be sure, much has been written extensively in description of utilization of bike oriented by supplier, for examples, Level of Service with bike path, infrastructure such as bicycle racks and lounge etc. Therefore, our study has been differentiated in development of new evaluation model focused on level of bike user's satisfaction, comprehensively considering suitability for bikeway installation, connectivity of the public transportation system and stability in Incheon City. ANP(Analytic Network Process) analysis which is able to allow consideration of the interdependence of criteria has been hired due to multi-collinearity instead of AHP used in multi-criteria decision analysis. Last but not least, we drew bike route on a case-by-case for maintenance and improvement of its facility in Namdong-gu and Bupyeong-gu. To conclude, suggested finding has dem onstrated the validity of evaluation scheme for bikeways which is appropriate for type and purpose and ultimately this can be used to establish policy decision making for improvement of bikeway.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.388-398
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• 2011

This study analyzes a correlation between organizational commitment, work values, job satisfaction and loyalty of the middle management in hotel enterprises. In other words, this research aims at drawing up theoretical and working-level implication through establishing the competition model of parameters and independent variables, which have an effect on loyalty of the middle management in hotels. Analysis showed that work values of the middle management play not a key role to mediate between organizational commitment and job satisfaction, and that internal values are higher than external values in route analysis of work values. Meanwhile, it was analyzed that the middle management of hotels make a long-service commitment with great satisfaction on the job. But there was no connection between their job satisfaction and loyalty. Consequently, it was confirmed through the analysis of the competition model that they rather attach significance to internal values and specificity of the hotelier than their satisfaction with work because of economic stability, and the loyalty of the middle management responds sensitively to the organizational commitment variables as a permanent job, sense of belonging, self-esteem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.9
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• pp.751-764
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• 2013

In cognitive radio ad-hoc networks, common control channel overload and packet collisions are occured due to indiscriminate broadcasting of control packets. So that the path reliability is reduced and control channel is easily saturated. In this paper, we propose a new routing algorithm considering the probability of appearance of primary user and channel status of neighbor nodes. When the source node needs to transmit a data packet to the destination, it performs route discovery process by exchanging control messages using a control channel in ADOV CR Ad-hoc networks. If any intermediate node doesn't have common data channel with previous node to transmit data, it doesn't rebroadcast control packet. And if it has common data channels with previous node, each node determines channel contribution factor with the number of common channels. Based on the channel contribution factor, each node performs different back-off broadcasting. In addition, each node controls control packet flooding by applying to proposed advanced mode using such as number of available channels and channel stability. With the proposed method, the number of control packets to find the data transmission path and the probability of collision among control packets can be decreased. While the path reliability can be increased. Through simulation, we show that our proposed algorithm reduces packet collisions in comparison with the traditional algorithm.

• Journal of Sensor Science and Technology
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• v.6 no.5
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• pp.369-375
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• 1997

$V_{2}O_{5}/ThO_{2}/Pd$-doped $SnO_{2}$ sensor has a good selectivity and stability to CO at high sensor temperature of about $500^{\circ}C$, and shows rapid response. In particular, many kinds of interference gases, such as $NO_{x}$, $C_{3}H_{8}$, $CH_{4}$ and $SO_{2}$ have been found to give only a slight influence on the sensor selectivity to CO gas sensitivity by doped $V_{2}O_{5}$ (3.0 wt.%). For the sensor we used well-known thick film technological route with $V_{2}O_{5}$(3.0 wt.%), Pd(1.0 wt.%) and $ThO_{2}$(l.5 wt.%) as catalytic materials. In the case of mixed $NO_{x}$-CO gases, as combustion exhaust gas, only CO detection by $SnO_{2}$ type semiconductor sensor is generally very difficult because of $NO_{x}$ interference. The developed sensors can use to measure the exhausting gas of the automobile or the boiler for the Air-to-Fuel ratio control.