디지털 통신이론의 개념적 범위 : 정보이론의 관점에서

송홍엽 연세대학교 산업기술연구소 2000 논문집 Vol.32 No.2

본 논문에서는 정보이론 혹은 수학적 통신이론의 관점에서 디지털 통신이론에 대한 범위와 기본 개념을 소개한다. 디지털 통신 모뎀의 기본적인 블록도와 구성요소에 대해서 설명한다. 마지막으로, 디지털 통신이론 흑은 정보통신 분야와 정보화 혹은 정보기술에서 다루는 정보에 대한 개념적 차이점을 논한다.

코스타스 어레이: 최적상관함수를 갖는 2차원 신호

송홍엽 연세대학교 산업기술연구소 1997 논문집 Vol.29 No.2

2차원 펄스 패턴에 대한 배경과 수학적 모델, 설계, 생성방법, 그리고 기타의 대수학적 관련 이론을 설명하고, 이와 관련된 여러 가지의 가설을 정리하여 소개하고자 한다. 코스타스 어레이는 그 정의에 의하여 상관특성(autocorrelation)이 최적이라는 성질을 가지므로, 능동소나시스템 뿐만 아니라 주파수이동(frequency hopping) 대역확산통신 시스템의 주파수천이시퀀스의 설계에, 그리고 PPM 통신 시스템이나 fiber-optic 통신 시스템의 펄스 위치 시퀀스 설계 등에 적절히 응용되어 많은 연구결과가 발표되고 있다.

Griesmer bound의 등호를 만족하는 [2^k-1+k, k, 2^(k-1)+1] 부호의 설계 방법

김정헌,송홍엽 연세대학교 전파통신연구소 2001 電波通信論文誌 Vol.5 No.1

모든□이진 부호는 Griesmer bound □를 만족해야 한다. 본 논문에서는 Griesmer bound의 등호를 만족하는 □부호의 간단한 설계법을 소개하고 Helleseth 부호 관점에서 본 새로운 표현법을 소개한다. Any □binary linear code must satisfy the Griesmer bound □Here, a simple construction of □codes which achieves the equality of the Griesmer bound is introduced and its another description in view of the codes of Helleseth is presented.

다양한 복호기의 구조를 갖는 터보 부호의 성능 분석

계환원,송홍엽 延世大學校 電波通信共同硏究所 1999 電波通信論文誌 Vol.4 No.1

터보 부호의 복호기는 복호화 알고리즘으로 MAP 알고리즘이나 SOVA 알고리즘을 이용하는 2개의 SISO(soft input soft output)복호기가 직렬 모드로 연결되어져서 반복적으로 정보들을 서로 교환하는 구조이다. 그러나 만약 병렬 모드로 복호기가 구성된다면 직렬 모드에 비해 더 많은 출력 정보를 얻을 수 있는 장점이 있다. 따라서 본 논문은 병렬 모드의 복호기 구조를 변형함으로써 성능의 개선을 얻을 수 있는 방법들을 제안한다. 바로 두 복호기들의 LLR 출력값을 더하는 방법과 두 복호기의 외부 정보의 평균값을 이용하는 방법이며 이렇게 제안한 방법과 일반적인 터보 부호의 성능과 비교, 분석한다. The decoders of turbo codes realized either using MAP algorithm or SOVA algorithm have the structures that two SISO(soft input soft output) decoders are concatenated in serial mode and exchange informations among each other. But if they are connected in parallel mode, more informations than in serial mode can be obtained. So this paper proposes the parallel decoder structures slightly modified in order to achieve performance improvement. The proposed methods are using the LLR outputs of two decoders and using the extrinsic informations of two decoders and compared with the performance of general turbo codes.

전자서명을 통한 인증기술과 공개키 기반구조에 대한 고찰

황재훈,박춘석,정연식,송홍엽 연세대학교 산업기술연구소 2000 논문집 Vol.32 No.2

전자서명과 인증의 정의 및 필요성과 개략적인 기술적 요소 등을 정리하고, 정보보호시스템의 보안에 대한 신뢰도를 향상시킬 수 있는 방향을 제안한다. 공개키의 인증문제를 해결하기 위해 발전된 공개키 기반구조, 즉 PKI에 대해서 살펴봄으로써 인증에 대한 심층적 고찰을 수행한다.

A Construction of Odd Length Generators for Optimal Families of Perfect Sequences

Song, Min Kyu,Song, Hong-Yeop IEEE 2018 IEEE transactions on information theory Vol.64 No.4

<P>In this paper, we give a construction of optimal families of <TEX>$N$</TEX>-ary perfect sequences of period <TEX>$N^{2}$</TEX>, where <TEX>$N$</TEX> is a positive odd integer. For this, we re-define perfect generators and optimal generators of any length <TEX>$N$</TEX> which were originally defined only for odd prime lengths by Park, Song, Kim, and Golomb in 2016, but investigate the necessary and sufficient condition for these generators for arbitrary length <TEX>$N$</TEX>. Based on this, we propose a construction of odd length optimal generators by using odd prime length optimal generators. For a fixed odd integer <TEX>$N$</TEX> and its odd prime factor <TEX>$p$</TEX>, the proposed construction guarantees at least <TEX>$(N/p)^{p-1}\phi (N/p)\phi (p)\phi (p-1)/\phi (N)^{2}$</TEX> inequivalent optimal generators of length <TEX>$N$</TEX> in the sense of constant multiples, cyclic shifts, and/or decimations. Here, <TEX>$\phi (\cdot )$</TEX> is Euler’s totient function. From an optimal generator one can construct lots of different <TEX>$N$</TEX>-ary optimal families of period <TEX>$N^{2}$</TEX>, all of which contain <TEX>$p_{\text {min}}-1$</TEX> perfect sequences, where <TEX>$p_{\text {min}}$</TEX> is the least positive prime factor of <TEX>$N$</TEX>.</P>

임의의 심볼 집합 상의 수열의 선형복잡도와 GF(p)상의 특성다항식을 갖는 GF($p^k$)상의 수열 생성에 관한 연구

Hong, Yun-Pyo,Eun, Yu-Chang,Kim, Jeong-Heon,Song, Hong-Yeop 한국통신학회 2003 韓國通信學會論文誌 Vol.28 No.5C

본 논문에서는 임의의 심볼 집합 상의 수열의 선형복잡도를 정의한다. 또한 본 논문에서는 기저의 선택과 상관없이 자신의 GF($p^{k}$ ) 상의 R-tuple 수열이 자신과 같은 특성다항식을 갖는 $p^{R}$-ary 수열의 특성을 밝히며 이는 결과적으로 GF(p) 상의 특성다항식을 갖는 $p^{+}$ -ary 수열의 생성을 가능하게 한다. 마지막으로 심볼이 GF(p) 상의 R-tuple로 표현될 때 기저의 선택과 무관하게 유일한 특성다항식을 갖는 $p^{R}$-ary 수열의 특성을 밝힌다. We propose an appropriate approach of defining the linear complexities (LC) of sequences over unknown symbol set. We are able to characterize those p-ary sequences whose R-tuple versions now eve. GF($p^{R}$ ) have the same characteristic polynomial as the original with respect to any basis. This leads to a construction of $p^{R}$ -ary sequences whose characteristic polynomial is essentially over GF(p). In addition, we can characterize those $p^{R}$ -ary sequences whose characteristic polynomials are uniquely determined when symbols are represented as R-tuples over GF(p) with respect to any basis.

Full Mouth Rehabilitation of a Patient with Bite Collapse in the Molar Area Using Removable Partial Denture and Dental Implant Prosthetics

Hong, Jun-Won,Seo, Jae-Min,Seong, Dong-Hwan,Song, Gwang-Yeop,Park, Ju-Mi,Ahn, Seung-Geun Korean Academy of Dental Science 2010 Journal of korean dental science Vol.3 No.2

Dental clinicians often encounter cases wherein the patient's lost molar area was neglected and left untreated for an extended period of time, thereby causing the extrusion of opposite molars and occlusal disharmony as well as occlusion in the anterior teeth and consequently resulting in anterior displacement in the area. Clinicians normally carry out prosthetic treatment via occlusal plane lifting when such becomes absolutely necessary due to the lack of sufficient space needed for prosthetic therapy aimed at proper anterior and lateral induction. In this case report, we examined occlusal disharmony and VDO loss in a patient who had lost his molars and had not received prosthetic treatment for an extended period of time. We treated the maxillary area with dental implant prosthetics and Kennedy Class I RPD and the mandibular area with residual natural tooth-based implant placement and dental implant prosthetics. The patient reported treatment outcomes that were deemed satisfactory both functionally and aesthetically.

Effects of Open Kinetic Chain Exercise for the Gastrocnemius and Tibialis Anterior Muscles on Balance

( Song Yeon Yi ),( Young Ju Kim ),( Dong Yeop Lee ),( Jae Ho Yu ),( Jin Seop Kim ),( Soung Gil Kim ),( Ji Heon Hong ) 대한물리치료학회 2021 대한물리치료학회지 Vol.33 No.6

Purpose: This study investigated the effects of open kinetic chain (OKC) exercise for the gastrocnemius (GCM) and tibialis anterior (TA) muscles on static and dynamic balance and muscle strength. Methods: We recruited 21 healthy participants, dividing them into 3 groups (GCM, TA, and non-exercise). Each group contains 7 participants. Two exercise groups (GCM and TA) performed OKC exercise with elastic bands twice per week for 4 weeks, while non-exercise group did nothing. We obtained the data for static and dynamic balance and muscle strength before and after the intervention. We used the Kruskal-Wallis test to compare and analyze the pre-post-intervention differences among the groups. Results: For static balance, the stability index of the TA group was the lowest for the dynamic platform (p<0.05). The dynamic balance of the TA group increased for the anterior and posteromedial directions (p<0.05). The peak torque increased in the TA group for dorsiflexion (D/F) movement and in the GCM group for plantar flexion movement compared with the other groups, except for the left direction during D/F (p<0.05). Conclusion: OKC exercises with elastic bands were effective for selectively increasing muscle strength. It is clinically thought that strength training for TA muscles will be effective among the muscles of the ankle.

Ultrasonic Bonding Interface Degradation Characteristics of Gold-Coated Silver Wire for Semiconductor Packaging

Mi-Song Kim(김미송),Won Sik Hong(홍원식),Sang Yeop Kim(김상엽),Sung Min Jeon(전성민),Jeong Tak Moon(문정탁) 대한용접·접합학회 2021 대한용접·접합학회지 Vol.39 No.4

Gold-coated silver wire was developed to alleviate the high cost of Au wire used in semiconductor packaging. Ball-bonding and stitch-bonding techniques were used to fabricate the dummy packaging material, comprising 97.3 % Ag, 97.3% Au-Coated Ag, and 99.99 %Au wires. The wire ball shear test (BST), the wire ball pull test (BPT), and the microstructural attributes of the ultrasonic bonding interfaces were compared with the initial properties, both before and after the highly accelerated stress test (HAST), conducted at 130 ℃ and 85% relative humidity (RH). The initial bonding strength for all the wire variants was ≈23~24 gf. Following the HAST, the bonding strength of the Ag wire, the Au-coated Ag wire, and the Au wire decreased by approximately 75 %, 47 %, and 17 %, respectively. The microstructure analysis revealed that cracks developed and propagated at the ends of the interface and that the Au-rich Au-Al intermetallic compound (IMC) inhibited the propagation of the crack at the ACA/Au wire interface. Additionally, it was discovered that the presence of the Ag-Au-Al IMC at the interface of the ACA wire reduced Kirkendall voids, which act as a barrier to Au-Al interdiffusion.