• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권5호
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• pp.1049-1068
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• 2011

In this paper a simple and effective call admission control (CAC) scheme is proposed for the emerging interleave-division multiple-access (IDMA) systems, supporting a variety of traffic types and offering different quality of service (QoS) requirements and priority levels. The proposed scheme is signal-to-interference-plus-noise ratio (SINR) evolution based CAC (SE-CAC). The key idea behind the scheme is to take advantage of the SINR evolution technique in the process of making admission decisions, which is developed from the effective chip-by-chip (CBC) multi-user detection (MUD) process in IDMA systems. By virtue of this semi-analytical technique, the MUD efficiency can be estimated accurately. Additionally, the computational complexity can be considerably reduced. These features make the scheme highly suitable for IDMA systems, which can combat intra-cell interference efficiently with simple CBC MUD. Analysis and simulation results show that compared to the traditional CAC scheme considering MUD efficiency as a constant, the proposed SE-CAC scheme can guarantee high power efficiency and throughput for multimedia traffic even in heavy load conditions, illustrating the high efficiency of CBC MUD. Furthermore, based on the SINR evolution, the SE-CAC can make accurate estimation of available resource considering the effect of MUD, leading to low outage probability as well as low blocking and dropping probability.

• 한국미생물·생명공학회지
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• 제48권1호
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• pp.12-23
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• 2020

Edible films containing antimicrobial agents can be used as safe alternatives to preserve food products. Essential oils are well-recognized antimicrobials. However, their low water solubility, volatility and high sensitivity to oxygen and light limit their application in food preservation. These limitations could be overcome by embedding these essential oils in complexed product matrices exploiting the encapsulation efficiency of β-cyclodextrin. This study focused on the maximization of β-cyclodextrin production using cyclodextrin glucanotransferase (CGTase) and the evaluation of its encapsulation efficacy to fabricate edible antimicrobial films. Response surface methodology (RSM) was used to optimize CGTase production by Brevibacillus brevis AMI-2 isolated from mangrove sediments. This enzyme was partially purified using a starch adsorption method and entrapped in calcium alginate. Cyclodextrin produced by the immobilized enzyme was then confirmed using high performance thin layer chromatography, and its encapsulation efficiency was investigated. The clove oil/β-cyclodextrin inclusion complexes were prepared using the coprecipitation method, and incorporated into chitosan films, and subjected to antimicrobial testing. Results revealed that β-cyclodextrin was produced as a major product of the enzymatic reaction. In addition, the incorporation of clove oil/β-cyclodextrin inclusion complexes significantly increased the antimicrobial activity of chitosan films against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella Typhimurium, Escherichia coli, and Candida albicans. In conclusion, B. brevis AMI-2 is a promising source for CGTase to synthesize β-cyclodextrin with considerable encapsulation efficiency. Further, the obtained results suggest that chitosan films containing clove oils encapsulated in β-cyclodextrin could serve as edible antimicrobial food-packaging materials to combat microbial contamination.

• 한국식품영양과학회지
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• 제46권9호
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• pp.1097-1105
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• 2017

본 연구는 돼지고기로 제조된 소시지에 저가원료인 닭고기 혼합비율을 정량하기 위해 real-time PCR 법과 소량 함유된 닭의 정량의 정확도를 높이기 위해 닭의 내부 표준물질을 첨가하는 방법을 적용함으로써 소시지의 진위판별 가능성을 제시하였다. DNA 회수율과 PCR 증폭효율을 높이기 위해 QIAamp DNA Micro Kit을 사용하였고, 최종 PCR 반응액 $20{\mu}L$에 template DNA($5{\sim}10ng/{\mu}L$)는 $3.0{\sim}5.0{\mu}L$, primer 농도는 $0.5{\mu}L(10pmol)$, $2{\times}$ Cybrgreen buffer는 $10{\mu}L$로 조정하였을 때 가장 적합하였고, PCR 증폭조건은 annealing 온도를 $62^{\circ}C$, extension 온도를 $68^{\circ}C$, final extension 시간은 33초, 최종 PCR cycle은 40 cycle로 했을 때 가장 PCR 증폭효율이 좋은 것으로 평가되었다. 돼지와 닭의 DNA를 50 ng에서 0.05 ng으로 순차적으로 10배씩 희석한 template DNA를 이용해 민감도(최소 검출한계)를 확인한 결과 돼지와 닭 모두 0.05 ng 이상으로 각각 확인되었다. 표준곡선의 결정계수($R^2$)도 모두 0.995 이상으로 표준곡선의 linearity가 정량에 적합한 것으로 확인되었다. 돼지고기와 닭고기를 각각 70:30 비율로 혼합한 3점의 시료를 $70^{\circ}C$에서 10분간 열처리한 후 정량분석을 실시하여 기대치에 의한 측정치를 비교한 결과, 64.3:35.7의 비율로써 평균 5.7%의 차이를 나타내 생육(raw meat) 또는 가열처리된 시료의 상태에 따라 DNA에 영향을 주어 PCR 증폭효율 및 DNA 정량 값에 일부 영향을 주는 것으로 판단되었다. 소시지에 함유된 돼지고기와 닭고기의 함량을 분석한 결과 돼지고기에 비해 닭고기 함량이 적은 소시지에서는 닭고기(6%, 12%, 25%, 38%)의 검출이 어려웠고, Ct(threshold cycle) 값에 따른 DNA 정량값이 매우 낮아 배합비율을 환산이 어려웠다. 그러나 소시지에 닭의 표준물질 DNA(50 ng)를 첨가함으로써 배합비율이 증가할수록 Ct값도 점차 낮아져서 배합비율을 반영하고 있음에 따라 Ct값의 평균치${\pm}$오차범위 값으로 간접적으로 배합비율을 추정할 수 있을 것으로 생각되었다.

• 한국인터넷방송통신학회논문지
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• 제8권6호
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• pp.97-103
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• 2008

최근에 제안된 수중 음향 센서 네트워크용 MAC 프로토콜인 T-Lohi는 저가형 음향 모뎀들이 밀집되어 구성된 네트워크에서 사용되도록 설계된 프로토콜이다. 그러나 T-Lohi는 각 노드들이 모든 노드들의 신호를 수신할 수 없어 멀티 홉 라우팅이 필요한 네트워크에서 사용될 때 hidden terminal 문제로 인해 많은 패킷 충돌이 발생한다. 본 논문에서는 T-Lohi처럼 톤을 사용하여 전력 소모에 있어서의 경제성을 추구하면서도 RTS/CTS handshaking을 통해 hidden terminal 문제를 해결한 새로운 MAC프로토콜을 제안한다. 모의실험 결과는 새로운 MAC프로토콜이 T-Lohi와 비교했을 때 패킷 손실을 훨씬 줄이면서도 좋은 네트워크 활용률을 달성할 수 있음을 보여준다.

• 대한기계학회논문집A
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• 제40권2호
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• pp.157-165
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• 2016

군용 전투 차량은 전시 상황에 여러 종류의 장애물들이 존재하는 험로를 주행해야 한다. 이런 환경에서는 전투 차량의 무거운 차체와 험로의 큰 장애물로 인해 큰 반력이 발생한다. 차륜형 견마 로봇에는 큰 장애물을 극복하기 위해서 회전형 현가장치가 적용되고, 미끄럼 조향 방식이 적용된다. 본 논문에서는 실시간 해석에 유리하도록 모델을 단순화시킨 방법을 제시하고, 기존 다물체 동역학 모델과 비교를 통해서 신뢰도 및 효율성을 확인하였다.

• 한국국방경영분석학회지
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• 제32권2호
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• pp.165-187
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• 2006

본 연구의 목적은 미래 네트워크중심전쟁에 부합하는 새로운 국방 군수지원체계의 구축방향을 제안하는 것이다. 이를 위하여 네트워크중심전쟁의 새로운 개념으로 미 국방부에서 연구하고 있는 SARL과 미래 군수정보체계에서 기술적인 혁신을 견인하는 정보 기술의 최근 발전을 결부하여 고찰하였다. 또한, 한국군에서 현재 사용되고 있는 군수 정보체계의 문제점을 분석하였다. 마지막으로 총 군수비용을 감소시키고 군수지원 속도를 향상하며 전투지원의 효율성을 향상시킬 수 있는 네트워크중심전쟁에서의 새로운 군수정보체계의 구축방향을 제시하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.32.1-32.7
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• 2019

Background: Tooth extraction commonly leads to loss of residual alveolar ridge, thus compromising the room available for the implant placement. To combat the post-extraction alveolar loss, alveolar ridge preservation is practiced, with the advent of the biomaterial available. The purpose of this study was to assess the efficiency of calcium phosphosilicate biomaterial in alveolar ridge preservation. Twenty patients indicated for extraction were selected followed by socket grafting using calcium phosphosilicate. Implant placement was done 6 months postoperatively during which a core was harvested from the preserved sockets. Clinico-radiographic measurements of hard and soft tissues were taken at baseline and 6 months post-grafting. Results: There were no significant changes in the radiographic and soft tissue parameters while significant changes in hard tissue parameters with 1.9 mm (p = 0.013) gain in mid-buccal aspect and 1.1 mm (p = 0.019) loss in horizontal bone width were observed. The histomorphometric evaluation depicted the vital bone volume of 54.5 ± 16.76%, non-mineralized tissue 43.50 ± 15.80%, and residual material 2.00 ± 3.37%. Conclusion: The implants placed in these preserved ridges presented 100% success rate with acceptable stability after a 1-year follow-up, concluding calcium phosphosilicate is a predictable biomaterial in alveolar ridge preservation.

• 한국통신학회논문지
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• 제36권4A호
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• pp.303-311
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• 2011

이 논문에서는 주파수 효율을 높이기 위하여 부분적으로 동일 부반송파를 할당한 MIMO(Multi-Input Multi-Out)-OFDMA(Orthogonal Frequency Division Multiplexing Access) 시스템에서 동일 부반송파 간섭과 다중 경로 신호를 제거하기 위한 다중 적응 빔 형성기법을 제안한다. 제안된 기법에 의해 간섭제거 이외에 다중 안테나로 부터 도착된 각 DOA마다 빔 패턴이 형성되어 다이바시티 이득을 얻을 수 있고 지연 시간에 따른 성능열화를 방지 할 수 있다. MIMO-OFDMA 시스템에 제안된 다중 적용 빔 형성기를 적용할 경우 성능 및 제시된 개선 효과를 모의 실험을 통하여 확인한다.

• 한국경영과학회지
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• 제39권2호
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• pp.37-48
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• 2014

Fighter squadron flight scheduling is the integrated air operation plan that is an important role for improving pilot's flight skill and maintaining combat readiness by efficient using available all air resources including pilot, aircrafts, air-weapons, fuel and supporting facilities etc. Korea airforce, however, has a limit as to an effective flight operation due to manual flight scheduling with scheduler's own experience and intuition. Therefore, in our study, we propose the optimization model of flight scheduling based on mixed integer programming. This model includes several constraints of realistic and essential quantified data related with flight schedule and can assign appropriate pilots optimally which are distinctive three type's solutions : flight, alert and duty crew schedules. Proposed solution method can be improved pilot's capability and allocated further air resources systematically and efficiently. In addition, it can be reduced a workload of flight scheduler and minimized obstructed factors of flight safety. Finally, we demonstrate the experiment's results for the check of efficiency and validity of this model.

• 한국의류학회지
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• 제46권5호
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• pp.910-926
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• 2022

Suitability for the human body, freedom to move and thermal insulation are important design considerations in military clothing. This study investigates the performance and wearer-satisfaction of the functional inner winter uniform currently used in Korea; it is hoped that our data can inform the development of a future version. Interviews were conducted, in which the participants suggested various improvements. The uniforms were mainly worn for guard duty or as daily attire in cold weather. The participants chose how many layers to wear according to the current situation, rather than sticking to the layering recommended in the manual. Layering choices did not significantly affect combat efficiency but were found to affect wearers' comfort. Wearers' satisfaction was found to depend on the convenience of the clothing, whether it was in the appropriate size, freedom to move and thermal insulation. Also, this study suggests a problem with the current size system, as the analysis of size distribution, across all sizes, the range of current production is insufficient to cover the demand.