• The Journal of the Korea Contents Association
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• v.6 no.7
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• pp.22-30
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• 2006

The goal of the company and profit maximization can be achieved by creating revenue or reducing costs. What can be done by the effort of the firm itself is possible through cost-reduction rather than through revenue-creation. Under this economic situation, one of the best way for cost-reduction is to reduce cost of logistics. But logistics costs of a firm is continually increased because of the various customer-satisfaction, competition. This study considers that logistics cost management system be able to apply business practice through to used only a merit of CVP(Cost - Volume Profit) analysis method for effective decision making. To conclude, this study depicts that logistics cost management according to used a merit of CVP analysis method can provide information useful for making strategy of logistics. In short, It is reduce to more costs of logistics investment than are necessary. and, I will expect a man who charge logistics to improvement, adaptation, and application.

• Journal of the Korean Graphic Arts Communication Society
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• v.31 no.1
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• pp.51-64
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• 2013

When it comes to current growth trend for the printing process in Asia printing market, offset printing, gravure printing and screen printing are reduced respectively -4%, -19%, -55%. In judging from the fact, the change in the printing production system from mass production on small amount to small production on mass amount is the biggest issue. For this reason, digital printing shows the significant growth. According to the increase of the growth 78% for electro photography way and 67% for ink-jet, it's not enough to catch up with digital printing which is increasing as time goes by to equip with hardware like as digital press. There's been necessary to install the BOD(Book on Demand) system which is the advanced and regular publication edit solution based on web-to-print model in the prepress, and it has made the BOD system be considered in relation to maximization of efficiency and production. Therefore, this research tries to step forward from the POD concept, which is refired to "Print along with the ordered quantities, the ordered appropriate time and the demanded place", so that it could expand the range of the printing/publishing environment using the BOD system, the order-made publication based on automatically operating template. And it tried to make the relation to digital web press on ink-jet method which is adequate to "mass production on small amount" with such advanced concept. This research also aims to use actively BOD solution model to promote the productivity of labor, and then to produce the printings across all related industries, which means to manufacture maximally the products on the shortest time at minimum place through PC equipments.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1417-1427
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• 2019

In this study, we evaluated the performance of a commercial pixelated cadmium zinc telluride (CZT) detector for spectroscopy and identified its feasibility as a Compton camera for radiation monitoring in a nuclear power plant. The detection system consisted of a $20mm{\times}20mm{\times}5mm$ CZT crystal with $8{\times}8$ pixelated anodes and a common cathode, in addition to an application specific integrated circuit. The performance of the various radioisotopes $^{57}Co$, $^{133}Ba$, $^{22}Na$, and $^{137}Cs$ was evaluated. In general, the amplitude of the induced signal in a CZT crystal depends on the interaction position and material non-uniformity. To minimize this dependency, a drift time correction was applied. The depth of each interaction was calculated by the drift time and the positional dependency of the signal amplitude was corrected based on the depth information. After the correction, the Compton regions of each spectrum were reduced, and energy resolutions of 122 keV, 356 keV, 511 keV, and 662 keV peaks were improved from 13.59%, 9.56%, 6.08%, and 5%-4.61%, 2.94%, 2.08%, and 2.2%, respectively. For the Compton imaging, simulations and experiments using one $^{137}Cs$ source with various angular positions and two $^{137}Cs$ sources were performed. Individual and multiple sources of $^{133}Ba$, $^{22}Na$, and $^{137}Cs$ were also measured. The images were successfully reconstructed by weighted list-mode maximum likelihood expectation maximization method. The angular resolutions and intrinsic efficiency of the $^{137}Cs$ experiments were approximately $7^{\circ}-9^{\circ}$ and $5{\times}10^{-4}-7{\times}10^{-4}$, respectively. The distortions of the source distribution were proportional to the offset angle.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.349-359
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• 2009

In this paper, we propose a stereo-video transmission method for reduction of delay and maximization of 3D effect. Conventional multimedia synchronization algorithms were designed to achieve minimum delay and synchronize multiple video and audio streams, however, they could not be effective for 3D video transmission. In this paper, we proposed a synchronization algorithm by considering the minimum error of time difference between streams for 3D effect. The minimum error of time difference for 3D effect was derived based on a 3D subjective quality test. We compute display time of the delivered videos within the allowed time-difference and the video are displayed according to the display time. To evaluate the performance of the proposed algorithm, we implemented a real-time video communication system and subjective quality test has been conducted with the proposed system. We found that video quality displayed by the proposed system. We found that video quality displayed by the proposed algorithm ranks 'good' and 'excellent' in the DMOS (Differential Mean Opinion Score) scale, based on the MOS (Mean Opinion Score) test.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9A
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• pp.784-789
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• 2011

In this paper, a precoder based on limited phase feedback is proposed to maximize user's receive signal-to-interference-plus-noise ratio (SINR) in coordinated multi-point (CoMP) coordinated scheduling / coordinated beamforming (CS/CB) precoding matrix indicator (PMI) scenario. Most conventional precoding techniques based on limited phase feedback have been considered in a single-cell environment. However, considering neighboring cells in a multi-cell environment, we enhance the conventional preocoding. method. First, to maximize receive SINR, precoding matrices are designed to maximize the serving cell's signal and to minimize the coordinated cells' signal. Also, a precoder which can be used in a limited bit feedback condition is suggested. Finally, the proposed precoder's performance is evaluated and compared with some other precoding techniques by using simulation under the CoMP CS/CB PMI scenario.

• Progress in Medical Physics
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• v.13 no.4
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• pp.209-217
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• 2002

There have been many studies on the application of the reciprocal advantages of multimodality image to define accurate target volume in the Process of radiation treatment planning. For the proper use of the multimodality images, the registration works between different modality images should be performed in advance. In this study, we selected chamfer matching method and mutual information method as most popular methods in recent image registration studies considering the registration accuracy and clinical practicality. And the two registration methods were analyzed to deduce the optimal registration method according to the characteristics of images. Lung phantom of which multimodality images could be acquired was fabricated and CT, MRI and SPECT images of the phantom were used in this study. We developed the registration program which can perform the two registration methods properly and analyzed the registration results which were produced by the developed program in many different images' conditions. Although the overall accuracy of the registration in both chamfer matching method and mutual information method was acceptable, the registration errors in SPECT images which had lower resolution and in degraded images of which data were removed in some part were increased when chamfer matching method was applied. Especially in the case of degraded reference image, chamfer matching methods produce relatively large errors compared with mutual information method. Mutual information method can be estimated as more robust registration method than chamfer matching method in this study because it did not need the prerequisite works, the extraction of accurate contour points, and it produced more accurate registration results consistently regardless of the images' characteristics. The analysis of the registration methods in this study can be expected to provide useful information to the utilization of multimodality images in delineating target volume for radiation treatment planning and in many other clinical applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.1081-1091
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• 2005

Unlike conventional DVB-T transmission with the streaming method, DVB-H system based on the IPDC(IP Data Casting) method uses Time-slicing scheme to achieve the maximization of portability by reducing the power consumption of a receiver. To enhance the power efficiency of the receiver, Time-slicing scheme controls the receiver operation to perform only for corresponding burst in specific time slot. The additional power saving can also be achieved by reducing the required time for synchronization. In this paper, we propose a fast scattered pilot synchronization algorithm, which detects the pilot pattern of currently received OFDM symbol. The proposed scheme is based on the correlation between the adjacent subcarriers of potential scattered pilot position in two consecutively received OFDM symbols. Therefore, it can reduce the time for the scattered pilot synchronization within two symbols as com-pared with the conventional method used for DVB-T. And the proposed algorithm has better performance than the two schemes proposed by Nokia for DVB-H and the method using correlation with reference signal. Extensive com-puter simulation is performed based on ETSI EN300 744 ETSI and performance results show that the proposed algorithm has more efficient and stable operation than the conventional schemes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.95-103
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• 2009

In this paper, a generation method of transmit and receive beamforming vectors based on base station cooperation is proposed which maximizes the user SINR in mobile cellular multi-user MIMO systems. There are two main sources of interference which deteriorate the performance of the system, i.e. the inter-user interference caused by the usage of the same radio resource for multiple users in the system, and the inter-cluster interference from neighboring base stations which are not participating in cooperative transmission. The proposed scheme cancels out the inter-user interference by using the block diagonalization(BD) method, and mitigate the inter-cluster interference by using optimal transmit and receive beamforming vectors based on optimal combining(OC) with the statistic information of inter-cluster interference. We perform computer simulations to verify the performance of the proposed scheme, and compare the result to the conventional performance obtained from utilizing the receiver side information only or utilizing the information from neither sides. The performance evaluations are conducted not only over the independent MIMO channels, but over correlated MIMO channels to demonstrate the robustness of the proposed scheme over the channels with correlation among antennas.

• Journal of Intelligence and Information Systems
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• v.12 no.1
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• pp.75-93
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• 2006

The ship selection by consignors has two steps to carry their cargo. The first step is to select according to time schedule of ships and amount of cargo, and the second one is re-selection by concentrating different consignors' cargo into a unit that can be carried by single ship. Up to now, these steps are usually done by hands leading to inefficiency. The purpose of our paper is to form a logistics chain to minimize the overall sum of logistics cost by selecting ships for consignors' cargo using negotiation methodology between agents. Through concentration and distribution of cargo, maximization of global profit derived from searching optimal point in trade-off between inventory cost and freight rate cost. It is settled by the negotiation between consignors. In the experiments, two methods of the first-step of ship selection: EPDS(Earliest Possible Departure-Date Scheduling) and LPDS(Latest Possible Departure-Date Scheduling) coupled with the second-step ship concentration method using the negotiation were shown. From this, we deduced inventory cost, freight rates and logistics cost according SBF(Scheduling Bundle Factor) and analyzed the result. We found it will minimize the total logistics cost if we use negotiation method with EPDS.

• Journal of Preventive Medicine and Public Health
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• v.31 no.4 s.63
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• pp.875-884
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• 1998

Missing observations are common in medical research and health survey research. Several statistical methods to handle the missing data problem have been proposed. The EM algorithm (Expectation-Maximization algorithm) is one of the ways of efficiently handling the missing data problem based on sufficient statistics. In this paper, we developed statistical models and methods for survey data with multivariate missing observations. Especially, we adopted the EM algorithm to handle the multivariate missing observations. We assume that the multivariate observations follow a multivariate normal distribution, where the mean vector and the covariance matrix are primarily of interest. We applied the proposed statistical method to analyze data from a health survey. The data set we used came from a physician survey on Resource-Based Relative Value Scale(RBRVS). In addition to the EM algorithm, we applied the complete case analysis, which uses only completely observed cases, and the available case analysis, which utilizes all available information. The residual and normal probability plots were evaluated to access the assumption of normality. We found that the residual sum of squares from the EM algorithm was smaller than those of the complete-case and the available-case analyses.