• 한국정보통신학회논문지
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• 제6권4호
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• pp.499-504
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• 2002

본 논문에서는 열잡음과 부분대역 재밍잡음 그리고 인접한 8개의 비트 패턴에 대한 심볼간 간섭을 고려하여 FH/CPFSK 시스템의 성능을 분석하였다. 이와 같은 FH/CPFSK 시스템의 분석을 위한 파라메타 비트율(bit rate)과 변조지수를 사용하였으며, 차동검파기(Differential Detector)를 이용한 최적 수신 상관함수 제시하고, FH/CPFSK 시스템과 FH/BFSK 시스템을 비교평가 하였다. 그 결과, 근사식과 실제식의 비트 오류 확률은 높은 신호대 잡음비에서 거의 일치함을 알 수 있었고, 재밍율에 따른 성능은 차동검파를 사용한 FH/CPFSK 시스템이 리미터-변별기를 사용한 FH/CPFSK 시스템 보다 3dB 성능이 떨어지나 FH/CPFSK 시스템보다는 2dB 성능이 우수함을 입증하였다.

• 대한화학회지
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• 제42권6호
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• pp.629-637
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• 1998

$6-31+G^{\ast}^{\ast}와\;6-311+G^{\ast}^{\ast}$의 기본조를 사용해서 이합체 분자착물 FH…FH, FH…CO, FH…OC 뿐만 아니라 $(HF)_2(CO)$의 형성가능한 두가지 삼합체 분자착물들에 대해서 HF-SCF, MP2 그리고 B3LYP 계산을 수행했다. 이 삼합체 분자착물들에 대한 여러 가지 바닥상태 성질들을 구하였으며, 대응하는 단위체들과 이합체들의 성질들과 비교하였다. FH…CO가 FH…OC에 비해 평균 0.85 kcal/mol 만큼 안정했고, F-H…F-H…C≡O가 F-H…F-H…O≡C 보다 1∼2 kcal/mol 만큼 안정한 것으로 계산되었다. 삼합체 분자착물 형성에 따른 C≡O stretching band 는 그들의 이합체들(FH…CO, FH…OC)에 비해 각각 24, $37\;cm^{-1}$만큼, H-F stretching band는 각각 $54, 353\; cm^{-1}$만큼 red shift 되는 것으로 평가되었다.

• 통합자연과학논문집
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• 제5권3호
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• pp.182-185
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• 2012

In this paper, For 4th generation wireless communication systems, we propose a method to predict FH patterns in FH-OFDMA systems. OFDM is recognized as a promising modulation technique. Multi-user allocation in OFDM system can use FH that provides the spectrum-spread techniques. If one can generate more predictable FH sequences, then performance of the system can be easily improved. Current random FH and simple adaptive FH methods, however, are not considering predicting FH sequences. In this paper we show that the sampling of the wireless faded signal is not realized as a certain probability nature. With this regard, the proposed predictive FH allocation method is designed to embed the unknown probability models. Simulation study shows that the predictive FH method is more accurately predict FH sequences than the random or simple adaptive FH methods. We will further improve this proposed method to apply QoS control and MAC function development in OFDMA based wireless physical structures, especially maritime wireless data communications.

• 지질동맥경화학회지
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• 제7권2호
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• pp.122-154
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• 2018

Familial hypercholesterolemia (FH) is typically associated with single gene mutation that is inherited by autosomal dominant manner. Due to high cardiovascular risk, aggressive discovery, diagnosis, and treatment of FH are critical. Although FH is being increasingly spotlighted, we do not have sufficient data on Korean patients with FH. Here, we present the content of symposium of the Education Committee, Korean Society of Lipid and Atherosclerosis held in May 2018: 1) epidemiology, clinical diagnosis, Korean FH data, and regulation in Korea; 2) genes associated with FH, sequencing process in suspicious proband, cascade screening, and difficulty in genetic diagnosis in FH; 3) the importance of lipid-lowering therapy in FH, conventional and novel therapeutics for FH; 4) diagnosis of FH in children and adolescence, screening, and treatment of FH in children and adolescence; 5) history of FH studies in Korea, the structure and current status of FH registry of Korean Society of Lipid and Atherosclerosis; and 6) difficulty in diagnosis of heterozygous and homozygous FH, drug intolerance and achievement of treatment target. Discussion between speakers and panels were also added. We hope that this article is helpful for understanding FH and future studies performed in Korea.

• 대한치과교정학회지
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• 제15권2호
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• pp.229-237
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• 1985

The Purpose of this study was to investigate the differences in soft tissue characteristics according to the dental or skeletal dysplasia. For this purpose, lateral cephalogram of 153 children (Hellman dental age IIIB: control group 32, Angle CIII. div. 1 malocclusion group 55, Angle Cl III group 66) were traced and measured. For these measurements, following conclusions were made. 1. FH A, FH Sn, FH UL, AA' of the Class III group were thicker than those of the normal and Class II group, but FH B, FH LL, BB' of the Class III group were not significantly different from those of the normal group. 2. FH B, FH LL, BB' of the Class II group were thicker than those of the normal and Class III group, but FH A, FH Sn, FH UL, AA' of the Class II group were not significantly different from those of the noraml group. 3. Ans-Sn, FH P were not significantly different in three groups, while PP' of the Class III group was thicker than those of the other groups. 4. The lower lips of the Class II group were more anterioly everted with respect to the lower incisor inclination than those of the other groups. 5. The severity of skeletal dysplasia was partly camouflaged by the soft tissue.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권3호
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• pp.123-129
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• 2014

Objectives: The aim of this study was to verify the concordance of the measurement values when the same cephalometric analysis method was used for two-dimensional (2D) cephalometric radiography and three-dimensional computed tomography (3D CT), and to identify which 3D Frankfort horizontal (FH) plane was the most concordant with FH plane used for cephalometric radiography. Materials and Methods: Reference horizontal plane was FH plane. Palatal angle and occlusal plane angle was evaluated with FH plane. Gonial angle (GA), palatal angle, upper occlusal plane angle (UOPA), mandibular plane angle (MPA), U1 to occlusal plane angle, U1 to FH plane angle, SNA and SNB were obtained on 2D cephalmetries and reconstructed 3D CT. The values measured eight angles in 2D lateral cephalometry and reconstructed 3D CT were evaluated by intraclass correlation coefficiency (ICC). It also was evaluated to identify 3D FH plane with high degree of concordance to 2D one by studying which one in four FH planes shows the highest degree of concordance with 2D FH plane. Results: ICCs of MPA (0.752), UOPA (0.745), SNA (0.798) and SNB (0.869) were high. On the other hand, ICCs of gonial angle (0.583), palatal angle (0.287), U1 to occlusal plane (0.404), U1 to FH plane (0.617) were low respectively. Additionally GA and MPA acquired from 2D were bigger than those on 3D in all 20 patients included in this study. Concordance between one UOPA from 2D and four UOPAs from 3D CT were evaluated by ICC values. Results showed no significant difference among four FH planes defined on 3D CT. Conclusion: FH plane that can be set on 3D CT does not have difference in concordance from FH plane on lateral cephalometry. However, it is desirable to define FH plane on 3D CT with two orbitales and one porion considering the reproduction of orbitale itself.

• 한국통신학회논문지
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• 제14권1호
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• pp.84-92
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• 1989

본 논문은 VHF 대역인 주파수 30-88MHz에서 TV 채널이 FH대역확산 통신의 전송채널에 포함되므로써 TV 영상이 받는 간섭의 정도와 그 주파수 양립성에 대하여 연구하였다. TV 신호의 전계강도는 송신 안테나로부터의 거리에 비례하여 감소하므로 FH 대역확산 신호가 TV 영상에 미치는 간섭정도도 이러한 TV 신호의 전계강도에 따라 달라진다. 그러므로 TV 신호의 전계강도에 따른 FH 대역확산 통신의 송신 출력과 TV 수신기와 FH 대역확산 송신기 사이의 거리의 관계에 의한 간섭 정도를 실험하였다. 본 논문에서의 실험 결과 FH 대역확산 간섭신호의 전력 level이 TV 영상신호의 전력 level보다 약 23.5dBm 이상 낮을 때 간섭신호의 영향을 받지 않았다. 따라서 이에 따른 TV 영상에 간섭을 초래하는 간섭거리를 유도하여 제시함으로써 FH대역확산 통신과의 주파수 공용으로 인한 간섭영향을 최소화 할 수 있도록 하였다.

• 한국정보통신학회논문지
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• 제9권4호
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• pp.693-697
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• 2005

본 논문에서는 Multi-Carrier 방식중의 하나인 MC DS/CDMA 방식과 대역확산 방식중의 하나인 주파수 호핑 방식을 결합한 FH MC-DS CDMA 시스템에서 SFH와 FFH를 적용하여 나카가미 페이딩 채널 하에서 멀티톤 재밍을 고려하여 시스템의 BER 성능을 비교 $\cdot$ 분석하였다. 호핑 횟수가 증가된다는 것은 주파수 다이버시티의 효과를 얻을 수 있게 되어 수신측의 부담을 줄이면서 FH MC DS/CDMA 시스템의 BER 성능을향상 시킬 수 있다는 것을 의미한다. 따라서 호핑 횟수를 증가시킴으로써 FH MC/DS CDMA 시스템의 성능을 개선할 수 있음을 입증하였다.

• Advances in nano research
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• 제12권6호
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• pp.605-616
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• 2022

We prepared two samples of ultrafine ferrihydrite (FH) nanoparticle ensembles of quite a different origin. First is the biosynthesized sample (as a product of the vital activity of bacteria Klebsiella oxytoca (hereinafter marked as FH-bact) with a natural organic coating and negligible magnetic interparticle interactions. And the second one is the chemically synthesized ferrihydrite (hereinafter FH-chem) without any coating and high level of the interparticle interactions. The interparticle magnetic interactions have been tuned by modifying the nanoparticle surface in both samples. The coating of the FH-bact sample has been partially removed by annealing at 150℃ for 24 h (hereinafter FH-annealed). The FH-chem sample, vice versa, has been coated (1.0 g) with biocompatible polysaccharide (arabinogalactan) in an ultrasonic bath for 10 min (hereinafter FH-coated). The changes in the surface properties of nanoparticles have been controlled by XPS. According to the electron microscopy data, the modification of the nanoparticle surface does not drastically change the particle shape and size. A change in the average nanoparticle size in sample FH-annealed to 3.3 nm relative to the value in the other samples (2.6 nm) has only been observed. The estimated particle coating thickness is about 0.2-0.3 nm for samples FH-bact and FH-coated and 0.1 nm for sample FH-annealed. Mössbauer and magnetization measurements are definitely shown that the drastic change in the blocking temperature is caused by the interparticle interactions. The experimental temperature dependences of the hyperfine field hf>(T) for samples FH-bact and FH-coated have not revealed the effect of interparticle interactions. Otherwise, the interparticle interaction energy E_int estimated from the hf>(T) for samples FH-chem and FH-annealed has been found to be 121k_B and 259k_B, respectively.

• 인터넷정보학회논문지
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• 제12권4호
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• pp.45-50
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• 2011

본 논문에서는 차량용 다중 카메라시스템에서 무선영상을 전송하기 위해 FH/TDD(Frequency Hopping/Time Division Duplex) 기반의 Motion JPEG 영상압축 코덱의 부호화 지연시간을 분석한다. 또한, Motion JPEG기반으로 FH/TDD에 의한 다중접속을 위해 시분할 시에 상호 동기화된 채널이동 과 접근방식(Synchronized shift & access)이 가능하도록 채널의 상태를 파악한 후, 채널충돌(Channel Collision)을 최소화하기 위한 동기화 연결(Synchronized connection) 방식을 설계한다.