• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.492-494
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• 2002

We established the job classification method that a classification standard is clear, and can subdivide job by using the raw data of time-and-motion study performed to analyze the medical staffs job elements. The final target of this study is to optimize job allocation and calculate human cost of medical staffs in hospitals.

• Journal of the military operations research society of Korea
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• v.24 no.1
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• pp.110-131
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• 1998

A stochastic modeling of combat that takes more realistic situations into account has been studied with deep concern. Either the firing strategies or network formations are very important elements in the analysis of combat. The first objective of this study is to evaluate how the different strategies affect the outcomes of combat. An analytical approach has been used in an attempt to understand a small-sized battle. The results are validated and compared with existing simulation models. Extending to the moderate size of battle may be achieved with ease. Secondly, an attempt has been made to study and investigate a way to solve combat in a different fashion. We divided a two-on-two battle into two separate one-on-one battles and connected them into a network. New elements considered such as delay time of starting a firefight on a particular node or search time for the next target when a kill occurs are defined and used as the input parameters. The discussions are made to validate the hypothesized model and ask if the results are meaningful and useful in the analysis of combat operations or not.

• ETRI Journal
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• v.37 no.5
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• pp.898-905
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• 2015

In this paper, we consider a joint beamforming and jamming design to enhance physical layer security against potential multiple eavesdroppers in a multiple-input and single-output cellular broadcast channel. With perfect channel state information at the base station, we propose various design approaches to improve the secrecy of the target user. Among the proposed approaches, the combined beamforming of maximum ratio transmission and zero-forcing transmission with a combination of maximum ratio jamming and zero-forcing jamming (MRT + ZFT with MRJ + ZFJ) shows the best security performance because it utilizes the full transmit antenna dimensions for beamforming and jamming with an efficient power allocation. The simulation results show that the secrecy rate of this particular proposed approach is better than the rates of the considered conventional approaches with quality-of-service and outage probability constraints.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.266-268
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• 2004

This paper presents the greenhouse gas emission trading scheme which is under progress as a pilot project at the power sector in preparation for UNFCCC. By referring UK's, Emission Trading is introduced incentive auction to maximize the reduction of greenhouse gas emission. At the 1st step, from year 2006 to 2008, only CO2 is regarded as an objective target to decrease but emission credit is excluded with an assumption and only 5 Generation company take part in as participants. The market operating procedure is composed of participants' registration, baseline verification, incentive auction, the registration of initial and yearly allocation, emission trading, yearly emission verification & approval, yearly obligation conformity, carry forward & incentive grant. It can be serve a guideline the whole aspects of emission trading which will start in 2006 including operation, verification and profit sharing.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.152-161
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• 2021

The paper focuses on Device-to-device (D2D) Architectures evaluation frameworks. D2D communication and discovery can improve spectrum usage efficiency and optimize the tradeoffs between throughput and energy consumption. The target operation modes involve both indirect communication between two nodes via a base station or the direct communication among proximal nodes, enabling use cases that can support communications out of cellular coverage, as well as low end-end delay requirements. The paper will present the architectural evolution of D2D networks within 3GPP standardization and will highlight key network functionalities and signaling protocols. It will also identify key analytical and simulation models that can be used to assess the performance and energy efficiency of resource allocation strategies, and it will present a suitable cross-layer integrated framework.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.12
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• pp.2534-2542
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• 2011

In this paper, we show that performance can be improved by using multiple antennas in the conventional orthogonal code hopping multiplexing (OCHM) scheme, which was proposed for accommodating a larger number of users with low channel activities than the number of orthogonal codewords used in code division multiple access (CDMA)-based communication systems through downlink statistical multiplexing. First, we introduce two different types of OCHM systems together with orthogonal codeword allocation strategies, and then derive their mathematical expression for log-likelihood ratio (LLR) values according to the two different schemes. Next, when a turbo encoder based on the LLR computation is used, we evaluate performance on the frame error rate (FER) for the aformentioned OCHM system. For comparison, we also show performance for the existing symbol mapping method using multiple antennas, which was used in 3GPP standards. As a result, it is shown that our OCHM system with multiple antennas based on the proposed orthogonal codeword allocation strategy leads to performance gain over the conventional system---energy required to satisfy a target FER is significantly reduced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1178-1190
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• 2009

IEEE 802.11e proposed by IEEE 802.11 working group to guarantee QoS has contention based EDCA and contention free based HCCA. HCCA, a centralized polling based mechanism of 802.11e, needs a scheduling algorithm to allocate the network resource efficiently. The existing standard scheduler, however, is inefficient to support for QoS guarantee for real-time service having VBR traffic. To efficiently assign resource for VBR traffic, in this paper, we propose TXOP algorithm based on dual leaky bucket using average resource allocation and peak resource allocation. The minimum TXOP of each station is obtained by using statistical approach to maximize number of stations of which performance satisfy QoS target. Simulation results show that the proposed algorithm has much higher performance compared with reference scheduler in terms of throughput and delay.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.57-66
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• 2010

In this paper, we propose the reliability constrained resource allocation scheduling algorithm in cellular network for uplink transmission, where uplink transmission is supported via packet switching schemes without the dedicated uplink circuit links. We evaluate the performance of the proposed algorithm, and compared with the conventional works to identify the pros and cons. The proposed uplink scheduling algorithm is to satisfy the constraints requirements of the MTC services which is considered as the core technology for future mobile wireless networks. It is different to conventional works which target to maximize the link capacity. The proposed algorithm provides reliable uplink transmission independent to the location and the quality of the wireless link of the mobile terminal. Based on the performance evaluation results, we conclude that the proposed method provides enhanced reliability performance than conventional works.

• International Area Studies Review
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• v.18 no.3
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• pp.3-21
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• 2014

The OECD DAC has recommended the member countries to raise the ODA budget by 0.7% of GNI. Most of DAC's members, howver, have not reached at the target level, mainly due to global economic crisis, with some exceptions in Northern Europe countries. Korea has increased the ODA budget allocation dramatically, but she could not still meet even the level 0.3%, which is the average level of DAC countries. In terms of national budget operation, DAC country groups are classified as the international norm type and the self-economic dependence type. And then, this study analyzes the time trends of the ODA budget in Korea, comparing with DAC's members on the economic scale. By forecasting Korean ODA budgets by country-type classifications, the optimal size of Korean government's ODA budget is proposed and discussed.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.59-66
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• 2009

This has been possible by integration techniques such as very large scale integration (VLSI) and wafer scale integration (WSI). Redundancy has been extensively used for manufacturing memory chips and to provide repair of these devices in the presence of faulty cells. If there are too many defects, the momory has to be rejected. But if there are a few defects, it will be more efficient and cost reducing for the company to use it by repairing. Therefore, laser-repair process is nedded for such a reason and redundancy analysis is needed to establish correct target of laser-repair process. The proposed CRA (Correlation Repair Algorithm) simulation, beyond the idea of the conventional redundancy analysis algorithm, aims at reducing the time spent in the process and strengthening cost competitiveness by performing redundancy analysis after simulating each case of defect.