• 대한조선학회논문집
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• 제55권1호
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• pp.37-44
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• 2018

To understand the dynamic characteristics of the vessel with hydroelastic response, it is very important to estimate the dynamic modal parameters such as mode shapes, natural frequency, and damping ratio. These dynamic modal parameters of full scale ship are a priori unknowns, hence to be estimated directly based upon the full scale measurement data. In this paper, dynamic modal parameters were extracted by signal processing of acceleration and strain data measured from a large container ship whose loading capacity is 9400TEU. The mode shapes of the vibrating hull were identified using the proper orthogonal decomposition and the vibration response of hull was decomposed into its modal magnitudes. Natural frequencies of specific modes were derived via Fourier transform of these modal magnitude. Also, the free decay signal of the vibrating hull was obtained through the random decrement technique and the damping ratio was estimated with accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권1호
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• pp.178-203
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• 2018

In this paper, authors have been evaluated the Frame Error Rate (FER) performance of IEEE 802.11 a/g/p standard 5 GHz frequency band WLAN over Rayleigh and Rician distributed fading channels in presence of Additive White Gaussian Noise (AWGN). Orthogonal Frequency Division Multiplexing (OFDM) based transceiver is implemented by using real-time signal processing frameworks (IEEE 802.11 Blocks) in GNU Radio Companion (GRC) and Ettus USRP N200 is used to process the symbol over the wireless radio channel. The FER is calculated for each sub-carrier conventional modulation schemes used by OFDM such as BPSK, QPSK, 16, 64-QAM with different punctuated coding rates. More precise SNR is computed by modifying the SNR calculation process of YANS and NIST error rate model to estimate more accurate FER. Here, real-time signal constellations, OFDM signal spectrums etc. are also observed to find the effect of multipath propagation of signals through flat and frequency selective fading channels. To reduce the error rate due to the multipath fading effect and Doppler shifting, channel estimation (CE) and equalization techniques such as Least Square (LS) and training based adaptive Least Mean Square (LMS) algorithm are applied in the receiver. The simulation work is practically verified at GRC by turning into a pair of Software Define Radio (SDR) as a simultaneous transceiver.

• 한국축산식품학회지
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• 제40권2호
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• pp.209-220
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• 2020

Milk fat globule membrane (MFGM) is a lipid carrier in mammals including humans that consists mainly of polar lipids, like phospholipids and glycolipids. In this study, a process to enrich polar lipids in commercial butter and whey powder, including polar lipids of MFGM, was developed. WPC (whey protein concentrate) 60 was selected as the most suitable raw material based on the yield, phospholipid, protein, and lactose content of the polar lipid fraction obtained by ethanol extraction of two WPC (WPC60 and WPC70) and two buttermilk (A and B). After fractionation under optimum conditions, the polar-lipid enriched fraction from WPC60 contained 38.56% phospholipids. The content of glycolipids, cerebroside, lactosylceramide, ganglioside GM3, ganglioside GD3, was 0.97%, 0.55%, 0.09%, and 0.14%, respectively. Rancimat results showed that the oxidation stability of fish oil increased with an increase in the polar-lipid fraction by more than 30 times. In addition, the secretion of IL-6 and TNF-α decreased in a concentration-dependent manner after treatment of RAW 264.7 cells with 0.1 to 100 ppm of the polar lipid fraction. In this study, polar lipid concentrates with antioxidant and anti-inflammatory activity, were prepared from milk processing by-products. The MFGM polar lipid concentrates made from by-products are not only additives for infants, but are also likely to be used as antioxidants in cooking oils and as active ingredients for functional foods.

• 전자공학회논문지A
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• 제31A권2호
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• pp.88-93
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• 1994

We fabricated a large-scale photovoltaic device for detecting-3-5$\mu$m IR, by forming of n$^{+}$-p junction in the $Hg_{1-x}Cd_{x}$Te (MCT) layer which was grown by LPE on CdTe substrate. The composition x of the MCT epitaxial layer was 0.295 and the hole concentration was 1.3${\times}10^{13}/cm^{4}$. The n$^{+}$-p junction was formed by B+ implantation at 100 keV with a does 3${\times}10^{11}/cm^{2}. The n$^{+}$ region has a circular shape with 2.68mm diameter. The vacuum-evaporated ZnS with resistivity of 2${\times}10^{4}{\Omega}$cm is used as an insulating layer over the epitaxial layer. ZnS plays the role of the anti-reflection coating transmitting more than 90% of 3~5$\mu$m IR. For ohmic contacts, gole was used for p-MCT and indium was used for n$^{+}$-MCT. The fabrication took 5 photolithographic masks and all the processing temperatures of the MCT wafer were below 90$^{\circ}C$. The R,A of the fabricated devices was 7500${\Omega}cm^{2}$. The carrier lifetime of the devices was estimated 2.5ns. The junction was linearly-graded and the concentration slope was measured to be 1.7${\times}10^{17}/{\mu}m$. the normalized detectivity in 3~5$\mu$m IR was 1${\times}10^{11}cmHz^{12}$/W, which is sufficient for real application.

• 한국항행학회논문지
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• 제2권1호
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• pp.53-60
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• 1998

대기권 전파에 따른 심각한 다중파 페이딩 채널인 HF 대역을 사용하는 장거리 항공이동 통신의 페이딩 영향을 극복하는 방안으로 RZ-SSB 방식을 도입하였다. RZ-SSB의 전송대역은 ARINC 규정에 기술되어 있는 AME 즉, 반송파를 삽입한 단측파대 통신방식과 유사하기 때문에 이러한 설계 파라미터를 활용한 송, 수신기를 설계하였다. 또한 설계 시에는 32비트 부동소수점 연산 DSP를 이용함으로써 신호의 질과 신뢰도를 향상시켰고, 이로 인하여 성능이 향상된 저중량, 저가격의 송, 수신기를 설계하였다. 리미터의 사용과 복조시 변조방식과 상이한 위상 복조의 개념을 도입하여 다중파 진폭 페이딩을 제거하였고, 또한 항공전자 시스템의 특성으로 RZ-SSB 방식의 근원적인 단점 또한 극복되고 항공통신에의 적용이 가능함을 실험 결과로 제시한다.

• 무역상무연구
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• 제64권
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• pp.65-97
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• 2014

Arbitration is the dispute methods for speedy and economic resolutions in international commercial areas. In maritime disputes cases in East Asia, Korea and Japan are the regional benefits to cover and deal with the maritime cases on arbitration. And Korea and Japan are the competitive maritime industry for heavy shipbuilding industry, cargo carrier, processing and transhipment service on ports, and ship financial services in national competitive areas. Japan is the Tokyo maritime arbitration commission(TOMAC) as an uniquely capable of dealing with arbitrations involving problems arising in the sea field. TOMAC provides amended its arbitration rules 2014 aiming at matching with the maritime disputes circumstances with three maritime arbitration rules as ordinary rules, simplified rules and the rules of small claims arbitration procedure. KCAB however, as the unique commercial arbitration board in Korea is dealing on all of the commercial disputes on only the international commercial arbitration rules in 2011. Though KCAB is dealt with maritime dispute cases on international arbitration rules in Korea, it is small and simple compared with TOMAC in Japan. Maritime disputes are highly complicated and embroiled with multi-parties contract and subcontracts arising under contracts relating to bills of lading, charter parties, sale and purchase of ships, shipbuilding, ship financing and so forth. This paper is to provides a discussion and comparison on recently arbitration rules focus on the maritime aspects on Korea and Japan. We need to consider to make an independent and special institute and maritime arbitration rules including the multiparty consolidation and med-arb provisions for handling the disputes and resolution of maritime conflict cases in Korea.

• 대한전자공학회논문지TC
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• 제38권4호
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• pp.18-26
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• 2001

본 논문에서는 극성 판단(Polarity Decision) PD를 이용하여 모드 변환과 루프이득(Loop Gain)의 변환시점을 자동적으로 검출해 주는 ATC(Automatic Transfer mode Control)알고리즘을 설계하고 모드 전환시 안정적으로 주파수 오프셋을 추정하는 평균방식 Gear-shift PLL을 설계하였다. 제안하는 모드 전환 시점 검출 알고리즘인 ATC 알고리즘은 종전의 QPSK방식에 적용되던 Lock Detector 알고리즘보다 구현이 매우 간단하며 정확하게 모드 전환시점을 검출한다. 또한 Shift Register에 저장했던 주파수 추정 값들을 평균하는 평균전환방식은 모드 전환시 낮은 주파수 추정 에러값으로 다음 모드에서의 빠른 추적 성능을 가능하게 한다. 본 논문에서 제안하는 알고리즘은 적은 회로 면적과 고속 처리가 가능하도록 설계되어 ASIC 설계에 매우 유용하다. 아울러 본 논문에서는 극성판단 PD를 적용하여 위상 포착 및 추적 성능평가를 수행하고 성좌도(constellation)를 각 모드별로 분석하였다.

• 한국항해항만학회지
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• 제39권6호
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• pp.479-484
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• 2015

네트워크 RTK는 네트워크 내 다중 기준국의 반송파 측정치 보정정보를 활용하는 정밀 측위 기법으로 성능 개선을 목적으로 꾸준히 연구가 진행되어 왔다. 최근까지는 주로 측지 측량 분야에서 사용하였기 때문에 정확도 개선을 위한 연구 위주로 진행되었으며, 무결성 확보를 위한 연구는 아직 미비하다. 본 논문에서는 네트워크 RTK에서의 무결성 확보를 위한 기초연구로 네트워크 RTK 환경에 적합한 감시 시스템을 설계하였다. 이를 위하여 네트워크 RTK에서의 무결성 결함 조건을 도출하고, 각 결함 조건 별로 활용할 수 있는 이상 검출 및 식별 기법을 소개하였으며, 이를 기반으로 네트워크 RTK를 서비스하는 중앙처리국에서 활용할 수 있는 감시 시스템을 설계하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.74-77
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• 2004

[ $HfO_2$ ] dielectric layers were grown on the p-type Si(100) substrate by metalorganic molecular beam epitaxy(MOMBE). Hafnium $t-butoxide[Hf(O{\cdot}t-C_4H_9)_4]$ was used as a Hf precursor and Argon gas was used as a carrier gas. The thickness of the layers was measured by scanning electron microscopy (SEM) and high-resolution transmission electron measurement(HR-TEM). The properties of the $HfO_2$ layers were evaluated by X-ray diffraction(XRD), high frequency capacitance-voltage measurement(HF C-V), current-voltage measurement(I-V), and atomic force measurement(AFM). HF C-V measurements have shown that $HfO_2$ layer grown by MOMBE has a high dielectric constant(k=19-21). The properties of $HfO_2$ films are affected by various process variables such as substrate temperature, bubbler temperature, Ar, and $O_2$ gas flows. In this paper, we examined the relationship between the $O_2/Ar$ gas ratio and the electrical properties of $HfO_2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.99-100
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• 2006

Silicon-on-insulator(SOI) MOSFET with SiGe/Si heterostructure channel is an attractive device due to its potent use for relaxing several limits of CMOS scaling, as well as because of high electron and hole mobility and low power dissipation operation and compatibility with Si CMOS standard processing. SOI technology is known as a possible solution for the problems of premature drain breakdown, hot carrier effects, and threshold voltage roll-off issues in sub-deca nano-scale devices. For the forthcoming generations, the combination of SiGe heterostructures and SOI can be the optimum structure, so that we have developed SOI n-MOSFETs with SiGe/Si heterostructure channel grown by reduced pressure chemical vapor deposition. The SOI n-MOSFETs with a SiGe/Si heterostructure are presented and their DC characteristics are discussed in terms of device structure and fabrication technology.