• Journal of Communications and Networks
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• 제16권6호
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• pp.627-638
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• 2014

In this paper, we study the joint price and power allocation in spectrum sharing macro-femtocell networks. The proposed game theoretic framework is based on bi-level Stackelberg game where macro base station (MBS) works as a leader and underlaid femto base stations (FBSs) work as followers. MBS has fixed data rate and imposes interference price on FBSs for maintaining its data rate and earns revenue while FBSs jointly adjust their power for maximizing their data rates and utility functions. Since the interference from FBSs to macro user equipment is kept under a given threshold and FBSs compete against each other for power allocation, there is a need to determine a power allocation strategy which converges to Stackelberg equilibrium. We consider two cases for MBS power allocation, i.e., fixed and dynamic power. MBS can adjust its power in case of dynamic power allocation according to its minimum data rate requirement and number of FBSs willing to share the spectrum. For both cases we consider uniform and non-uniform pricing where MBS charges same price to all FBSs for uniform pricing and different price to each FBS for non-uniform pricing according to its induced interference. We obtain unique closed form solution for each case if the co-interference at FBSs is assumed fixed. And an iterative algorithm which converges rapidly is also proposed to take into account the effect of co-tier interference on interference price and power allocation strategy. The results are explained with numerical simulation examples which validate the effectiveness of our proposed solutions.

• 한국공작기계학회논문집
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• 제13권4호
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• pp.44-55
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• 2004

In order to meet the requirement for higher thickness accuracy in tandem cold rolling processes, it is strongly necessary to have good performance in control units. To meet this requirement, this paper suggested an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation and roll eccentricity simultaneously as the major disturbances, a synthesis of multivariable control systems was presented based on H$\infty$ control theory, which could reflect the knowledge of input direction and spectrum of disturbance signals on design. Then, to effectively reject roll eccentricity, a weight function having some poles on the imaginary axis was introduced. This lead to a non-standard H$\infty$ control problem, and the design procedures for solving this problem were analytically presented. The effectiveness of the proposed control method was evaluated through computer simulations and compared to that of the conventional linear quardratic control and feedforward control methods for roll eccentricity.

• Journal of Mechanical Science and Technology
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• 제18권1호
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• pp.45-54
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• 2004

In order to meet the requirement for higher thickness accuracy in cold rolling processes, it is strongly desired to have high performance in control units. To meet this requirement, we have considered an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation as well as roll eccentricity as the major disturbances, a synthesis of multivariable control systems is presented based on H$\sub$$\infty$/ control theory, which can reflect the knowledge of input direction and spectrum of disturbance signals on the design. Then, to reject roll eccentricity effectively, a weight function having some poles on the imaginary axis is introduced. This leads to a non-standard H_ control problem, and the design procedures for solving this problem are analytically presented. The effectiveness of the proposed control method is evaluated through computer simulations and compared to that of the conventional LQ control and feedforward control methods for roll eccentricity.

• 경영과학
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• 제30권1호
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• pp.125-137
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• 2013

The U.S. Army is capable and ready to deploy full-spectrum armed forces anywhere in the world as we have seen in Iraq and Afghanistan. This commitment is within the realm of logistics support that the readiness to support MRE(Meal Ready to Eat), according to the environment where the operation is on going. ROKA(Republic Of Korea Army) proceeds with the program to develop and reserve various MRE under the assumption of distinctive warfare operating environment. This study investigates to determine the amount of MRE consumption within various operating environment and details are as follows. First we ponder the concept of MRE and identified problems of the existing program. Second we also establish feeding rations by the types of MRE that is the base for calculation. Third we introduce MRE consumption algorithm and formula. Fourth and last we have applied our model to the program and analyzed the results. The present state of the estimation didn't reflect various warfare operating environment. Therefore we simulates theater wargame model to determine the consumption under various warfare operating environment. The result of this study is anticipated to contribute largely to the force enhancement as it mirrors of every circumstances of operating environment.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.591-593
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• 2016

Device-to-device (D2D) communications underlaid cellular infrastructure is an competitive local area services technology to promote spectrum usage for next generation cellular networks. These potential can only be tap through efficient interference coordination. Previous works only concentrated on interference from D2D pairs whiles interference from CUs to D2D pairs were neglected. This work focus on solving uplink interference problem emanating from multiple CUs sharing its resource with multiple D2D pairs. The base station (BS) acting as a supervisor selfishly institute a pricing scheme to manage the interference it experience from D2D pairs based on its Quality of service (QoS) requirement. D2D pairs following the supervisor make power allocation decisions considering the price from the BS in a non-cooperative game fashion. In order for the D2D pairs to also meet their QoS requirement, they suggest a price to the BS called discount price which reflects the interference they receive from the CUs. Finally, we analyze the proposed approach.

• 한국정보통신학회논문지
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• 제19권7호
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• pp.1546-1553
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• 2015

인지 라디오 기술에서는 통신 대역의 우선권을 가지고 있는 일차 시스템이 대역을 사용하지 않을 때 이차 시스템이 기회 적으로 대역을 활용하게 함으로써 추가적 주파수 할 당 없이 전체 통신 시스템의 수율을 향상시킨다. 따라서 인지 라디오 기술에서는 일차 시스템의 대역 사용 여부를 판단하는 기술인 대역 센싱이 매우 중요하다. 본 연구에서는 인지 라디오 기술을 사용하는 셀룰러 시스템에서 이종 일차 시스템이 공존하는 환경에서의 협력 대역 센싱에 대해서 다루었다. 특히 일차 시스템이 다양한 전송 파워 및 센싱 요구 조건을 가지고 있어서 이차 시스템의 일부 단말들만 일차 시스템의 존재를 인지 할 수 있을 경우를 고려한 다중 스테이지 센싱 기반 협력 센싱 기술을 제안하였다. 또한 기존에 제안된 OR-rule, AND-rule, MAJORITY-rule 기반 협력 센싱 방안들의 성능을 이종 일차 시스템 환경에서 분석하였다. 시뮬레이션을 통해 제안 방안이 기존 방안들에 비해 높은 정확도로 일차 시스템 존재 여부를 판단할 수 있음을 확인하였다.

• 한국미생물·생명공학회지
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• 제7권3호
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• pp.127-133
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• 1979

5'-GMP의 직접발효생산균주의 분리목적으로 Breuibacterium ammoniagenes ATCC 6871에 자외선조사 및 NTG, DES 등의 변이제처리를 한 결과 guanine계 핵산관련물질을 직접 배지중에 축적하는 변이주는 분리할 수 없었으며, adenine영양요구주로써 GMP-reductase가 결핍되고 adenosine 및 AMP에 의해 생육저해를 받지 않는 변이주가 XMP-aminase activity가 현저히 높았음을 알았다. 이러한 변이주중 BA-17-2가 XMP-aminase의 activity가 가장 높았으며 또한 전환된 5'-GMP를 GDP나 GTP로 거의 인산화하지 않았으며 그리고 guanosine이나 guanine으로 분해하지 않았다. 생성된 5'-GMP를 anion exchange resin Duolite 102 D를 사용하여 분리하고 ultraviolet 및 Infra-red spectrum을 조사한 결과 5'-GMP로 동정되었다.

• Nuclear Engineering and Technology
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• 제45권7호
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• pp.921-928
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• 2013

A future nuclear energy system is being developed at Korea Atomic Energy Research Institute (KAERI), the system involves a Sodium Fast Reactor (SFR) linked with the pyro-process. The pyro-process produces a source material to fabricate a SFR fuel rod. Therefore, an isotopic fissile content assay is very important for fuel rod safety and SFR economics. A new technology for an analysis of isotopic fissile content has been proposed using a lead slowing down spectrometer (LSDS). The new technology has several features for a fissile analysis from spent fuel: direct isotopic fissile assay, no background interference, and no requirement from burnup history information. Several calculations were done on the designed spectrometer geometry: detection sensitivity, neutron energy spectrum analysis, neutron fission characteristics, self shielding analysis, and neutron production mechanism. The spectrum was well organized even at low neutron energy and the threshold fission chamber was a proper choice to get prompt fast fission neutrons. The characteristic fission signature was obtained in slowing down neutron energy from each fissile isotope. Another application of LSDS is for an optimum design of the spent fuel storage, maximization of the burnup credit and provision of the burnup code correction factor. Additionally, an isotopic fissile content assay will contribute to an increase in transparency and credibility for the utilization of spent fuel nuclear material, as internationally demanded.

• 전자공학회논문지
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• 제54권7호
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• pp.3-11
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• 2017

무인기 시스템은 무인기 시장이 확대됨에 따라 다수 무인기의 동시 운용을 위한 충분한 주파수 대역 할당에 한계가 있다. 또한, 무인기의 이동성으로 인해 실시간으로 무인기 네트워크 통신환경이 급변한다. 따라서 무인기 시스템의 안정적인 운용 및 전송 data rate를 최대로 하기 위해서는 한정된 주파수 대역폭 안에서 주어진 네트워크 환경을 고려한 효율적인 자원할당이 필요하다. 본 논문에서는 TDMA(Time Division Multiple Access)를 기반으로 주어진 네트워크 환경에서 무인기 운용을 위한 최소 데이터 요구사항을 만족시키는 동시에 네트워크 처리율을 최대로 하는 자원할당 알고리즘을 제안한다. 성능분석을 통해 제안한 알고리즘은 주어진 네트워크 환경에서 최소 데이터 요구사항을 만족하면서 높은 네트워크 처리율을 만족시키는 자원할당이 가능함을 입증하였다.

• The Korean Journal of Pain
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• 제24권1호
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• pp.7-12
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• 2011

Background: Adenosine has been shown to have a wide spectrum of unique pain-relieving effects in various clinical situations. The aim of this study was to investigate the effects of intraoperative adenosine infusion on acute opioid tolerance and opioid induced hyperalgesia induced by remifentanil in adult patients undergoing tonsillectomy. Methods: For this study, ninety patients were randomly allocated into groups that receive either adenosine (adenosine group) or saline (remifentnail group) intravenously under remifentanil based anesthesia and saline (sevoflurane group) under sevoflurane anesthesia. The patients in adenosine group received adenosine at dose of $80\;{\mu}g$/kg/min, and those in remifentnail group and sevoflurane group received an equal volume of saline 10 minutes after the induction of anesthesia until the end of surgery. Intraoperative evaluation included time weighted mean remifentanil dose, and postoperative evaluations included degree of pain severity at 1, 6, 12, and 24 hours, time to first postoperative requirement, and analgesic dose required during 24 hours after operation. Results: Time weighted mean remifentanil dose during intraoperative period in adenosine group was significantly lower than that of remifentnail group (P = 0.00). The first postoperative analgesic were required earlier in remifentanil group than sevoflurane group or adenosine group (P = 0.00). Pethidine requirement during 24 hours in sevoflurane group and adenosine group was significantly lower than that of remifentnail group (P = 0.00). The visual analog scale scores for pain in sevoflurane group and adenosine group were significantly lower than those of remifentnail group for 12 hours after operation (P = 0.00). Incidence of hypotension (P = 0.024) and number of ephedrine administered (P = 0.011) in adenosine group were significantly higher than those of sevoflurane group. Conclusions: The above results suggest that intraoperative adenosine infusion prevent acute opioid tolerance and opioid induced hyperalgesia induced by remifentanil.