주파수 영역에서 구간조건을 이용한 음향학적 반향 제거

이규호(Kyu-Ho Lee),장준혁(Joon-Hyuk Chang) 大韓電子工學會 2009 電子工學會論文誌-SP (Signal processing) Vol.46 No.5

본 논문은 적응 반향 제거기인 parametric wiener filter (PWF)의 반향신호 제거 파라미터를 구간 조건에 따라 차등적으로 적용시키는 새로운 음향학적 반향제거 (Acoustic Echo Suppression, AES) 알고리즘을 제안한다. PWF는 반향 신호 추정의 부정확성을 보상하고자 반향신호 제거 파라미터를 사용한다. 기존의 방법은 단일통화 구간과 동시통화 구간에 관계없이 동일한 반향신호 제거 파라미터 값을 적용하여 동시통화 환경에서 근단 신호의 왜곡을 발생 시킨다. 본 논문에서는 상관계수 (Correlation Coefficient)를 이용한 동시통화(Double-Talk) 검출 알고리즘과 음성구간검출기 (Voice Activity Detector, VAD)의 결과로부터, 원단 화자만 있는 구간과 동시통화 구간을 구분하고 각각의 경우에 반향제거 파라미터를 달리 적용하여 동일한 반향신호 제거 파라미터를 사용함에 따른 동시통화 구간내의 근단 화자신호의 음질 저하 없이 반향신호를 보다 효과적으로 제거하는 방법을 제안한다. 제안된 방법의 결과는 객관적인 실험을 통해 비교 평가한 결과 우수한 성능을 보였다. In this paper, we propose a novel approach of an acoustic echo cancellation (AEC) algorithm which is differently adopted in the relevant period condition by the suppression parameter of a parametric wiener filter (PWF). The PWF uses the suppression parameter to compensate uncertainty of acoustic echo signal estimation. The existing PWF method using the fixed suppression parameter derives the distortion of the near-end signal at the double-talk. To solve this problem, the boundary condition is devised using decision of the double-talk detection (DTD) algorithm and voice activity detector (VAD). The boundary condition makes it possible to treat differently depending on the case of the single-talk and double-talk. According to the experimental results, the proposed approach is found to be effective for acoustic echo cancellation using the boundary condition.

노조/무노조 부문 병행전략의 성격과 의미

이정현 한국고용노사관계학회 2019 産業關係硏究 Vol.29 No.1

The purpose of this study is to examine the features of the double-breasted strategy which have both unionized and non-unionized plants, based on a case study of the Valero Energy Corporation, the largest U.S. independent refinery company. The two research questions here are analyzed, 1) what the success factors of the double-breasted strategy adopted by the company are and 2) whether union substitution approach differs clearly from union suppression approach in that case. The adoption of the double-breasted strategy was an incontestable success to the company, in terms of the three criteria, blockage of unionization proliferation, maintenance of low union density and minimization of strike damage. It is shown that the success factors of union substitution approach in Valero are such as salary level around average of industry and the best level of fringe benefits in the industry, no lay-off policy and no outsourcing policy of HRM, manpower policy emphasizing corporate culture and teamwork, effective communication between company and individual employees, well-functioned ADR system, very selective M&A, vertical/horizontal firewall against union organizing drive, professional services from various consulting firms, and so on. As the economic situation around Valero from 2008 had become worse, many measures, which are regarded as union suppression approach, were also implemented, such as lay-off, pre-emptive sellout of plants with higher union density, outsourcing jobs held by union members, unfair labor practice regarding positive employee conduct, massive ‘vote No’ campaign, cautious employee selection, ValPAC, and so on. It is found that Valero, which had pursued the union substitution approach, also adopted the union suppression approach in parallel. In addition, it is inevitable to examine various aspects of labor relations in detail, in order to understand the real features of union avoidance strategy fully, as well as to pay attention to the characteristics of human resource management system. Also the result implies that Valero’s double-breasted strategy and union avoidance strategy is closely interwoven with the conservative political climate in Texas, the Right-to-Work Act system, local sentiments, regional infra-structures supporting non-unionism industry as well as the internal human resource management and labor relations mechanisms. 이 글의 목적은 무노조기업의 노조/무노조 부문 병행전략(double-breasted strategy)의 선택 및 실행과정, 실행의 상세 내용, 실행의 효과 등을 살펴보는것이다. 아울러 인적자원관리 문헌들이 시사하는 것처럼 미국 우량기업의 병행전략이 노조대체적 내용으로 일관되고 있는지, 노조억압적 내용들도 포함되는지를 검토하고자 한다. 이러한 목적을 위하여 이 글은 미국 최대 독립 정유회사이자 텍사스 기반 무노조기업인 Valero Energy를 사례로 분석하였다. 1980년 설립 이래 무노조기업이었던 Valero는 유노조 공장들을 잇달아 인수하면서 2000년대 노조/무노조 병행전략의 노사관계를 시작하였다. 노조화확산 방지, 낮은 노조조직률 유지, 파업 피해 최소화 등의 기업 측 기준으로볼 때, 21세기 Valero의 병행전략은 성공적이었다. 높은 임금 및 복리후생 제공, 고용보장, 지역중시 문화, 효과적 의사소통 추구, 선별적 기업/공장 인수, 노조화 확산 차단을 위한 수직적·수평적 차단벽 활용, 전문 로펌 활용 등으로구성된 노조대체접근이 그 성공의 주요 원인이었다. 하지만 2009년 경기불황이후 정리해고 실시, 노조조직률이 높은 공장의 우선 매각 및 노조 직무 축소또는 외주화, 긍정적 종업원 행동규범 강제의 부당노동행위, 노조화 반대 캠페인 실시, 선별적 채용 및 정치활동위원회 등 불법의 소지가 상당한 노조억압접근 역시 사용되었다. 종합하면, 세계적인 우량기업에서조차도 노조대체전략이 노조억압전략과맞닿아 있음을 발견하였다. 이는 사회 차원에서의 노조조직률 제고를 위해서병행전략 추구 기업의 노조억압적 모습을 규제하는 정책적 관심이 필요함을시사한다. 또한, 기업의 인적자원관리 제도에만 주목해서는 특정 기업의 노조/무노조 병행전략과 노조회피전략의 성격을 올바로 파악하는 것이 어려우며,노사관계의 여러 특징들을 세밀하게 검토하는 것이 불가피하다. 본 논문은Valero의 노조/무노조 병행전략 및 노조회피전략이 기업 내부의 인적자원관리와 노사관리 측면의 메커니즘뿐만 아니라, 텍사스 지역의 보수적 정치풍토와 노조의무가입금지법(Right-to-Work Act), 지역의 무노조주의 지원 인프라등과 밀접하게 연관되어 있음을 밝혔다.

Intermittent Addiction and Double Sidedness of Thought Suppression: Effects of Student Smart Phone Behavior

양회창,김영이 한국유통과학회 2015 유통과학연구 Vol.13 No.9

Purpose – This study investigates the effects of thought suppression on depression and uneasiness among college students likely to be influenced by smart phone addiction. Research design, data, and methodology – A total of 151 valid questionnaires were collected. The following analyses were conducted using SPSS 19.0 and AMOS 19.0: frequency, descriptive statistics, correlation, simple regression, and multiple regression. Results – Smart phone addiction increased uneasiness, depression, impulsiveness, and aggression. Moreover, uneasiness, depression, impulsiveness and aggression from smart phone addiction, had a negative influence on psychological wellbeing resulting in potential delinquent behavior. In addition, the addiction treatment relied heavily on drugs; therefore, such psychological treatment should be strengthened to control intermittent addiction. Conclusions – The results indicate that various kinds of research are needed to investigate personality and environmental factors that influence smart phone addiction. Additionally, studies on lessening smart phone addiction and living healthy lifestyles are needed. Moreover, psychological rehabilitation and treatment should be developed to lessen the rebound effect after thought suppression, to verify the effects of clinical application, and to prevent intermittent addiction.

Vibration suppression of a double-beam system by a two-degree-of-freedom mass-spring system

Mohammad Rezaiee-Pajand,Ahmad Aftabi Sani,Seyed Mojtaba Hozhabrossadati 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.21 No.3

This paper investigates the free vibration analysis of double-beam system coupled by a two-degree-of-freedom mass-spring system. In order to generalize the model, the main beams are assumed to be elastically restrained against translation and rotation at one end and free at the other. Furthermore, the mass-spring system is elastically connected to the beams at adjustable positions by means of four translational and rotational springs. The governing differential equations of the beams and the mass-spring system are derived and analytically solved by using the Fourier transform method. Moreover, as a second way, a finite element solution is derived. The frequency parameters and mode shapes of some diverse cases are obtained using both methods. Comparison of obtained results by two methods shows the accuracy of both solutions. The influence of system parameters on the free vibration response of the studied mechanical system is examined.

A Single-Stage 12-Times Frequency Multiplier for a 5G Frequency Synthesizer

임성우,남규현,박준석 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.3

This paper presents a single-stage 12-times frequency multiplier composed of an invented harmonic generator (HG) and a modified cascode buffer. The reliable output frequency band is guaranteed from 16 GHz to 28 GHz (54.5% frequency range). The whole band is divided to 256 subsidiary frequency bands by applying 8-bit digitally controlled capacitor banks of LC (inductor and capacitor)-tuned output. The invented HG architecture is based on a double-balanced mixer, but the bottom and top differential pairs are appropriately biased to generate the required turn-on time, , for obtaining the more dominant desired 12th harmonic. In addition, to reduce power consumption and conversion gain variation for the target frequency band, a negative-gm differential pair is added to the HG core in parallel to enhance the equivalent parasitic resistance, which is directly proportional to the HG gain. Newly created automatic constant amplitude control is able to keep the HG amplitude output constant as well as keep it from oscillating. Further desired harmonic amplification and unwanted suppression can be achieved by the proposed cascode buffer. The proposed 12-times multiplier is fabricated on a 65-nm CMOS (complementary metal-oxide-semiconductor) process and successfully tested. Chip die size is 0.4 mm2, and power consumption is only 4 mW.

Intermittent Addiction and Double Sidedness of Thought Suppression: Effects of Student Smart Phone Behavior

Hoe-Chang Yang,Young-Ei Kim 한국유통과학회 2015 유통과학연구 Vol.13 No.9

Purpose – This study investigates the effects of thought sup-pression on depression and uneasiness among college students likely to be influenced by smart phone addiction. Research design, data, and methodology – A total of 151 val-id questionnaires were collected. The following analyses were conducted using SPSS 19.0 and AMOS 19.0: frequency, de-scriptive statistics, correlation, simple regression, and multiple regression. Results – Smart phone addiction increased uneasiness, de-pression, impulsiveness, and aggression. Moreover, uneasiness, depression, impulsiveness and aggression from smart phone ad-diction, had a negative influence on psychological wellbeing re-sulting in potential delinquent behavior. In addition, the addiction treatment relied heavily on drugs; therefore, such psychological treatment should be strengthened to control intermittent addiction. Conclusions – The results indicate that various kinds of re-search are needed to investigate personality and environmental factors that influence smart phone addiction. Additionally, studies on lessening smart phone addiction and living healthy lifestyles are needed. Moreover, psychological rehabilitation and treatment should be developed to lessen the rebound effect after thought suppression, to verify the effects of clinical application, and to prevent intermittent addiction.

복층터널 자동 모니터 소화설비를 이용한 화재진압 실험

박진욱,유용호,김휘성,박병직,김양균 한국화재소방학회 2017 한국화재소방학회논문지 Vol.31 No.6

As one of the solutions to deal with economic loss caused by traffic congestion in metropolitan area, a deep undergroundroad has been planned and implemented at home and abroad. The part of them has been pushed ahead with a double-deckscheme which has an advantage in constructability and cost efficiency comparing to traditional road tunnel. However, thedouble-deck tunnel has a lower floor height than the general road tunnel due to the special structure used as the upper andlower lines by installing the middle slab on one excavation section. Therefore, it is relatively weak against fire accidents andventilation problems occurring in tunnels. Thus study to develop the life safety system optimized to a double-deck tunnel hasbeen systematically carried out in order to overcome their weak point. In this study, automatic monitoring fire extinguisher(AMFE) is developed to suppress a fire and prevent its spread at early stage of tunnel fire, conducting the performance testthrough vehicle fire tests as verification. The tests were conducted with AMFE being 30 m apart from the vehicle and 10m apart from engine room. As a results, it was confirmed that AMFE enables to suppress a fire and prevent its spread inboth cases. 대도심지의 교통 체증 문제로 발생되는 경제적 손실의 해결방안으로 대심도 지하도로 개발이 국내외적으로 대두되고 있으며, 이 중 일부는 시공성 및 경제성이 뛰어난 복층터널로 계획되고 있다. 그러나 복층터널은 하나의 굴착단면에 중간 슬래브를 설치하여 상‧하행선으로 사용하는 특수한 구조로 인해 일반 터널보다 층고가 낮게 설치되어 터널내에서 발생되는 화재사고 및 환기 문제에 대해 비교적 취약하다. 따라서, 복층터널의 방재적 약점을 극복하기 위해서는 복층터널에 최적화된 방재 설비구축 연구가 국내에서도 체계적으로 수행되어야 한다. 본 연구에서는 복층터널 화재 안전성 향상을 위해 화재발생시 초기 화재 진압 및 확산 방지가 가능한 자동모니터소화설비를 개발하였으며, 차량화재 진압 실험을 통해 성능시험을 수행하였다. 그 결과로부터 30 m 거리의 차량내부화재 및 10 m 거리의 엔진룸 화재에 대해 화재 확산 방지 및 진압 효과를 확인하였다.

Vibration suppression of a double-beam system by a two-degree-of-freedom mass-spring system

Rezaiee-Pajand, Mohammad,Sani, Ahmad Aftabi,Hozhabrossadati, Seyed Mojtaba Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.21 No.3

This paper investigates the free vibration analysis of double-beam system coupled by a two-degree-of-freedom mass-spring system. In order to generalize the model, the main beams are assumed to be elastically restrained against translation and rotation at one end and free at the other. Furthermore, the mass-spring system is elastically connected to the beams at adjustable positions by means of four translational and rotational springs. The governing differential equations of the beams and the mass-spring system are derived and analytically solved by using the Fourier transform method. Moreover, as a second way, a finite element solution is derived. The frequency parameters and mode shapes of some diverse cases are obtained using both methods. Comparison of obtained results by two methods shows the accuracy of both solutions. The influence of system parameters on the free vibration response of the studied mechanical system is examined.

복층터널 화재대응을 위한 원격 자동소화시스템 개발 연구

박진욱,유용호,김양균,박병직,김휘성,박상헌 사단법인 한국터널지하공간학회 2019 한국터널지하공간학회논문집 Vol.21 No.1

'To effectively deal with the fire in tunnel which is mostly the vehicle fire, it’s more important to suppress the fire at early stage. In urban tunnel, however, accessibility to the scene of fire by the fire fighter is very limited due to severe traffic congestion which causes the difficulty with firefighting activity in timely manner and such a problem would be further worsened in underground road (double-deck tunnel) which has been increasingly extended and deepened. In preparation for the disaster in Korea, the range of life safety facilities for installation is defined based on category of the extension and fire protection referring to risk hazard index which is determined depending on tunnel length and conditions, and particularly to directly deal with the tunnel fire, fire extinguisher, indoor hydrant and sprinkler are designated as the mandatory facilities depending on category. But such fire extinguishing installations are found inappropriate functionally and technically and thus the measure to improve the system needs to be taken. Particularly in a double-deck tunnel which accommodates the traffic in both directions within a single tunnel of which section is divided by intermediate slab, the facility or the system which functions more rapidly and effectively is more than important. This study, thus, is intended to supplement the problems with existing tunnel life safety system (fire extinguishing) and develop the remote-controlled automatic fire extinguishing system which is optimized for a double-deck tunnel. Consequently, the system considering low floor height and extended length as well as indoor hydrant for a wide range of use have been developed together with the performance verification and the process for commercialization before applying to the tunnel is underway now. 차량화재가 대부분인 터널 화재 사고에 효과적으로 대응하기 위해서는 초기에 화재를 진압하는 것이 가장 효율적이다. 그러나 도심지 터널의 경우 화재 사고시 차량 정체로 인해 소방대 투입이 어려워 신속한 소화 활동에 제약을 받으며, 이러한 문제는 최근 장대화 및 대심도화 되고 있는 지하도로(복층터널)의 경우 더욱더 심하게 나타날 것으로 판단된다. 국내의 경우 터널에서 발생되는 재난 ‧ 재해에 대비하여 터널연장과 터널 조건별로 정해지는 위험도 지수를 토대로 연장등급과 방재등급을 산정하여 방재시설 설치 범위를 규정하고 있으며, 특히 터널 화재에 직접적으로 대응하기 위한 설비로소화기구, 옥내소화전설비, 물분무설비 등을 등급에 따라 기본시설로 지정하고 있다. 그러나 이런 소화설비는 현실적으로 기능적이고 기술적인 측면에서 많은 약점이 발생되어 개선방안이 필요한 실정이다. 특히, 하나의 단면을 중간 슬래브로 나눠 상하행선으로 사용하는 형태인 복층터널의 경우 일반 소화설비보다 더 신속하고 효과적으로 화재 진압이 가능한 설비가 필요할 것으로 판단된다. 따라서 본 연구에서는 기존 터널 방재시설(소화설비)이 가지는 문제점을 보완하고, 복층터널의 구조적 특수성에 최적화된 원격 자동소화 시스템을 개발하였다. 그 결과로 낮은 층고를 고려한 장거리용 설비와 보급성을 확대한 옥내소화전용 설비 등 두 가지 형태의 시스템 개발을 완료하여 성능을 검증하였으며, 실제 터널에보급되어 널리 활용될 수 있도록 현재 실용화를 추진 중에 있다.

평행 결합 Mushroom 구조를 이용한 대역 통과 여파기의 고조파 성분 억제

이재곤,이정해,Lee, Jae-Gon,Lee, Jeong-Hae 한국전자파학회 2007 한국전자파학회논문지 Vol.18 No.2

본 논문에서는 평행 결합 버섯 구조를 이용하여 대역 통과 필터의 고조파 성분을 제거하였다. Double positive(DPS)전송 선로인 마이크로스트립 라인과double negative(DNG)전송 선로인 버섯 구조 사이에서는 격리된 마이크로스트립 라인과 버섯 구조의 교차되는 분산 곡선 주파수 대역에서 강한 결합이 복소 전파 상수로 인해서 발생한다. 교차되는 분산 곡선 주파수에서 강한 결합으로 인하여 전파가 전파를 하지 못하기 때문에 이와 같은 구조는 대역 저지 필터로 이용할 수 있는 것이다. 제안된 대역 저지 필터는 공진기를 이용한 형태가 아니라 평행 결합 전송 선로를 이용하였기 때문에 넓은 대역폭을 가지고 DPS와 DNG 전송 선로 사이의 강한 결합으로 인해서 소형화에 유리하다는 장점을 가지고 있다. 본 논문에서는 중심 주파수 4 GHz, 3 dB fractional 대역폭은 40%인 평행 결합 대역 저지 필터를 설계하였고, 이를 두 가지 종류의 대역 통과 필터의 고조파 모드를 억제하는데 이용하였다. Harmonic band of bandpass filter(BPF) is suppressed using coupled mushroom structure. Between double positive (DPS) transmission line such as microstrip and double negative(DNG) transmission line such as one dimensional mushroom structure, strong coupling broadly arises in the cross range of dispersion curves of isolated microstrip and mushroom structure because of complex propagation constant in the cross range. Strong coupling inhibits wave propagation, so that this kind of structure can be utilized as bandstop filter(BSF). This BSF utilizes coupled transmission line instead of coupled resonator, resulting in broad bandwidth(>30 %), shan-rejection, and high rejection level. The strong coupling between DPS and DNG transmissionline makes it possible shorten coupling length, resulting in compact size. In this paper, parallel coupled BSF having center frequency of 4 GHz and 3 dB fractional bandwidth of 40 % is designed and utilized to suppressed spurious mode of two bandpass filters.