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G.729 코덱의 패킷 손실 영향 모델을 이용한 비 침입적 음질 예측 기법
이민기,강홍구,Lee, Min-Ki,Kang, Hong-Goo 한국음향학회 2013 韓國音響學會誌 Vol.32 No.2
본 논문은 패킷 손실의 영향을 이용한 비 침입적 음질 평가 방법을 제안한다. 패킷 손실은 패킷 기반의 통신 시스템에서 음질을 저하시키는 주된 요소이며 그 영향은 코덱에 내장된 패킷 손실 은닉 알고리듬에 의해 결정된다. 패킷 손실 영향을 반영한 음질평가 시스템을 위해 VoIP 에서 협대역 코덱으로 사용되는 코덱 중 하나인 G.729를 선택하였으며, 음성 특징에 따른 패킷 손실 영향을 구분하기 위해서 G.729 코덱의 음성 파라미터를 이용한 한 음성 특성 분류기를 설계하였다. 이후, 각각의 패킷 특성에 따른 음질 저하의 정도를 수치화하기 위해 원 PESQ-LQ점수와 상관계수를 최대화하는 음질 저하 가중치를 반복적으로 구하였으며, 최종 음질 저하는 가중합으로 구하였다. 그 결과 제안한 모델과 PESQ-LQ의 상관계수는 칩입 모델 에서는 0.8950를, 비 침입 모델 에서는 0.8911의 결과를 나타내었다. This paper proposes a non-intrusive speech quality estimation method considering the effects of packet loss to perceptual quality. Packet loss is a major reason of quality degradation in a packet based speech communications network, whose effects are different according to the input speech characteristics or the performance of the embedded packet loss concealment (PLC) algorithm. For the quality estimation system that involves packet loss effects, we first observe the packet loss of G.729 codec which is one of narrowband codec in VoIP system. In order to quantify the lost packet affects, we design a classification algorithm only using speech parameters of G.729 decoder. Then, the degradation values of each class are iteratively selected that maximizes the correlation with the degradation PESQ-LQ scores, and total quality degradation is modeled by the weighted sum. From analyzing the correlation measures, we obtained correlation values of 0.8950 for the intrusive model and 0.8911 for the non-intrusive method.
이민기,박근우,Lee, Min-Ki,Park, Kun-Woo 대한기계학회 1997 大韓機械學會論文集A Vol.21 No.1
The determination of the direct kinematics of the parallel mechanism is a difficult problem but has to be solved for any practical use. This paper presents the efficient formulation of the direct kinematics for double parallel robot arm. The robot arm consists of two parallel mechanism, which generate positional and orientational motions, respectively. These motions are decoupled by a passive central axis which is composed of four revolute joints and one prismatic joint. For a set of given lengths of linear actuators, the direct kinematics will find the joint displacements of th central axis from geometric constraints in each parallel mechanism. Then the joint displacements will be converted into the position and the orientation of the end effector of the robot arm. The proposed formulation is decoupled and compacted so that it will be implemented as a real-time direct kinematics. With the proposed formulation, we analyze the motion of the double parallel robot and show its characteristics. Specially, we investigate the workspace in terms of positional space as well as orientational space.
이민기,김태성,박근우,Lee, Min-Ki,Kim, Tae-Sung,Park, Kun-Woo 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.11
This research develops a low-cost and high accuracy kinematic calibration method based on the following principles: 1) the platform locations are accurately measured by a constrained movement to inspect a calibration target; 2) the constrained movement is chosen to guarantee the parameter observability; 3) the mechanical fixture to constrain the movement and the sensor to check the constrained movement are implemented by low-cost and high-accuracy devices; 4) the calibration is easily done at an industrial environment. The kinematic parameters calibrated with respect to a single plane aren't influenced due to the misalignment of the plane. A parameter observability is successfully obtained even through one planar constraint, which guarantees that all kinematic parameters are estimated by minimizing the cost function.
연구품질 향상을 위한 프로세스 관점의 R&D 품질 진단 프레임워크 개발
이민기(Min-Ki Lee),이해준(Hae-Jun Lee),이종석(Jong-Seok Lee),신완선(Wan-Seon Shin),한근희(Keun-Hee Han),김덕환(Deok-Hwan Kim) 대한산업공학회 2017 대한산업공학회지 Vol.43 No.2
Evaluating the performance of R&D Activity is complicated because it is hard to quantify the R&D results unlike the traditional manufacturing or service industries. Recently, to overcome this, process-focused evaluation methods applying the philosophy of quality into R&D environment have been introduced. However, these quality activities are mainly conducted without feedback system after the evaluation work is done. The aim of this study is to present a R&D quality diagnosis framework to obtain the improvement opportunities from R&D process perspective. The research is designed as follows : First, R&D standard process and R&D quality elements are derived from a literature review. Second, the diagnosis objects are obtained by investigating the R&D quality elements at each R&D steps. Third, a two-dimensional diagnosis model, which enables the objective measurement of the ‘system compatibility’ and ‘accomplish level’, is presented. The proposed method can provide an effective way to find opportunities for efficient quality improvement of R&D process.
Gantry Type 공작기계의 CROSS RAIL 처짐량 측정 및 분석
이민기(Min Ki Lee),박재범(Jae Beom Park),김남성(Nam Sung Kim),민들레(Deul Le Min),이응석(Eung Suk Lee) 한국생산제조학회 2010 한국공작기계학회 추계학술대회논문집 Vol.2010 No.-
This study of purpose is to predict and to compensate displacement of Cross Rail of Gantry type when Spindle Head is moving on Y-axis anywhere. For composition of experiment is Mahr probe, Mahr Millitron 1240, A/D converter. As moving 500kg of mass block, measure displacement and compare with analytical result which load is acting on Y-axis at certain location so we show method of compensation and it is possible and efficient one of others. The analysis is carried out by FEA simulation using ANSYS also we induce equation.
저항성 운동이 OLETF 쥐의 혈청 염증반응지표 및 고환조직의 CatSper 1-4 단백질 발현에 미치는 영향
이민기 ( Min-ki Lee ),박세환 ( Se-hwan Park ),윤진환 ( Jin-hwan Yoon ) 한국운동생리학회(구 한국운동과학회) 2017 운동과학 Vol.26 No.3
PURPOSE: This study was to investigate the effects of resistance exercise on serum inflammatory markers and CatSper 1-4 expression in testis of OLETF rats. METHODS: Male OLETF rats were divided into two groups; control group (n=12), resistance exercise group (n=12). The exercise group performed a total of 8 weeks of moderate intensity resistance exercise on a 1.35 m vertical ladder with weights secured to their tails. RESULTS: The results of this study was following; The exercise group showed a significant decreased in the inflammatory (IL-1β, IL-6, TNF-α) levels as compared to the control group. But CRP was no significant difference between control and exercise groups. Also, CatSper 1 and 2 were significantly increased in the exercise group compared to the control group, whereas CatSper 3, 4 were no significant difference between both groups. CONCLUSIONS: This study suggests that resistance exercise training can contribute to reduce pro-inflammatory responses in whole body and it affects male reproductive function by improve sperm quality and CatSper protein expression.
소셜 네트워킹을 위한 감성-기반 인터페이스의 설계 및 구현
이민기 ( Min-ki Lee ),이기영 ( Ki-young Lee ) 한국정보처리학회 2010 한국정보처리학회 학술대회논문집 Vol.17 No.2
최근 세계적으로 소셜 네트워킹에 대한 관심과 스마트폰의 기술이 발전함에 따라 사용자를 위한 다양한 인터페이스가 요구되고 있다. 항상 사용자의 손이 닿는 곳, 바로 옆에 위치한 모바일 단말기에서 다양한 센서를 집약하여 감정을 인식하고 인식된 정보와 위치 정보를 결합하여 세계적으로 관심이 높은 소셜 네트워킹의 인터페이스를 설계하고 구현하였다.
이민기 ( Min-ki Lee ),김헌웅 ( Heon-woong Kim ),이선혜 ( Seon-hye Lee ),게릴라아사메누 ( Gelila Asamenew ),이수지 ( Suji Lee ),최용민 ( Yongmin Choi ),박진주 ( Jin Ju Park ),이상훈 ( Sang-hoon Lee ),김정봉 ( Jung-bong Kim ) 한국환경농학회 2019 한국환경농학회 학술대회집 Vol.2019 No.-
Capillary wormwood (Artemisia capillaris Thunberg) and crown daisy (Chrysanthemum coronarium L.) belonging to Family Asteraceae have been regarded as traditional medicinal herbs for preventive effects against chronic diseases including vascular disease, diabetes mellitus, and obesity. These plants are known for major resource of diverse caffeoylquinic acid (CQA) derivatives and flavonoid glycosides. Thus, objective of this study was to observe effects on high thermal and pressure processing to their CQA derivatives from capillary wormwood and crown daisy. A total of twenty-six hydroxycinnamoylquinic acid (HCQA) derivatives including p-coumaroylquinic acids (21), CQAs (3), and feruloylquinic acids (2) were separated and identified using UPLC-DAD-QToF/MS. Among them, a total twelve of HCQA derivatives was newly reported. Capillary wormwood and crown daisy were presented great majority of 5-O-caffeoylquinic acid (chlorogenic acid) and 3,5-di-O-caffeoylquinic acid (isochlorogenic acid A). In addition, 3,5-di-O-caffeoyl-4-O-succinylquinic acid was predominant compound in crown daisy. The total contents of HCQA derivatives were tended to decrease slightly during high thermal and pressure processing. Especially, the CQA derivatives which were esterified at 5- position of quinic acid moiety including chlorogenic acid and isochlorogenic acid A were tended to convert 3- and 4- position of CQA derivatives during processing. Therefore, proper high thermal and pressure processing is possible to enhance active ingredients. Furthermore, it can give valuable information for future research of functional foods and drugs.