• Title/Summary/Keyword: OTM

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Time-division Multiplexing Scheme for Analog Response Analysis (시분할 멀티플렉싱 기법을 이용한 아날로그 회로응답 분석)

  • 노정진
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.40 no.2
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    • pp.126-136
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    • 2003
  • We propose a new technique to improve the parametric fault coverage of oscillation test method (OTM). The OTM has been popular as a vectorless scheme for analog circuit test, both as a general defect-oriented technique, as well as an oscillation built-in self- test (BIST) scheme. However, it still requires improvement in several aspects. This paper analyzes the limitation of OTM, and proposes new signature analysis scheme to improve its performance.

System Level Performance Evaluation of TICN Based on Mobile WiMAX (Mobile WiMAX 기반 TICN의 시스템 레벨 성능평가)

  • Yun, Ju-Hee;Kim, Jaekwon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.8
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    • pp.5233-5241
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    • 2014
  • This study analyzed the system level performance of the Mobile WiMAX-based TICN, and the effects of the use of BS-OTM in terms of the throughput of individual users as well as the overall system, assuming that other stationary BSs are distributed randomly. When BS-OTM is used, the CINRs decrease due to the additional interference from the BS-OTM from the perspective of SSs that are served by the same BS as when OTM BS is not used. On the other hand, from the perspective of SSs that had low CINRs, the CINRs increase significantly due to the new service from BS-OTM. Considering both effects, the cell throughput can be increased using BS-OTM. The CINR distribution and throughput of the overall system, changing the carrier frequency, position and velocity of the BS-OTM were also evaluated.

Performance Analysis of Cooperative Communication with Spread Spectrum to Overcome Channel Blockage for On-The-Move Terminal in Next Generation Satellite Communication Systems (차기 군 위성통신체계 환경에서 이동형 위성단말의 채널 blockage 극복을 위한 확산기반 협업통신 기법의 성능 분석)

  • Park, Hyung-Won;Lee, Ho-Sub;Yoon, Won-Sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.9
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    • pp.757-766
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    • 2014
  • To compensate signal loss due to the channel blockage in satellite communication link, we propose a cooperative communication scheme for OTM(On-The-Move) terminal in next generation satellite communication systems. The proposed scheme configures cooperation subnet with adjacent OTM terminal with the help of ground communication equipment. Shared data is spread by orthogonal spreading code, then the spread sequences are transmitted simultaneously. The receiver combines the power of received signals by EGC(Equal gain combining). The OTM terminal blockage channel is modeled by 2-state Markov chain. We evaluate the bit error rate according to the blockage channel of the channel state for the performance analysis of the proposed scheme. As a result, the proposed scheme shows better BER performance than traditional scheme with the help of subset members. In particular, the proposed scheme shows superior performance as the channel block probability is higher. However, as the number of subset members is increasing, there is a constraint because of the higher multiple access interference.

Biomechanical adaptation of orthodontic tooth movement (임상가를 위한 특집 2 - 교정력에 의한 치아이동과 Biomechanical adaptation)

  • Lee, Syng-Ill
    • The Journal of the Korean dental association
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    • v.51 no.3
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    • pp.138-147
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    • 2013
  • Orthodontic tooth movement is a unique process which tooth, solid material is moving into hard tissue, bone. Orthodontic force in general provides the strain to the PDL and alveolar bone, which in turn generates the interstitial fluid flow(in detail, fluid flow in PDL and canaliculi). As a results of matrix strain, periodontal ligament cells and bone cells are deformed, releasing variety of cytokines, chemokines, and growth factors. These molecules lead to the orthodontic tooth movement(OTM). In these inflammation and tissue remodeling sites, all of the cells could closely communicate with one another, flowing the information for tissue remodeling. To accelerate the rate of OTM in future, local injection of single growth factor(GF) or a combination of multiple GFs in the periodontal tissues might intervene to stimulate the rate of OTM. Corticotomy is effective and safe to accelerate OTM.

LOS(line-of-sight) Stabilization Control of OTM(on-the-move) Antenna Driven by Geared Flexible Transmission Mechanism (기어와 유연축을 갖는 구동계로 구동되는 OTM 안테나 시선의 안정화 제어)

  • Kang, Min-Sig;Yoon, Wo-Hyun;Lee, Jong-Bee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.10
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    • pp.951-959
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    • 2011
  • In this study, an OTM(on-the-move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite while moving was addressed. Since LOS(line-of-sight) of antenna should direct satellite consistently while vehicle moving to guarantee high satellite communication quality, active antenna LOS stabilization is a core technology for OTM antenna. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. In consideration of driving mechanism which consists of gear train and flexible driving shafts, a two-mass-system dynamic model coupled with vehicle motion was presented. An internal PI-control loop + outer PI-control loop structure has been suggested in order to damp the torsional vibration and stabilize control system. The classical pole-placement method was applied to design control gains. In addition, a vehicle motion compensation control beside of the feedback control loop has been suggested to improve LOS stabilization performances. The feasibility of the proposed control design was verified along with some experimental results.

Orthodontic tooth movement after periodontal regeneration of intrabony defects

  • Conchita Martin;Mariano Sanz
    • The korean journal of orthodontics
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    • v.54 no.1
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    • pp.3-15
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    • 2024
  • The prevalence of intrabony defects in patients with advanced periodontitis stages III and IV is high. These patients usually need both periodontal treatment and orthodontic therapy, including tooth movement through bone defects, to improve masticatory function, aesthetics, and overall quality of life. Clinical practice guidelines recommend periodontal regenerative surgical interventions to resolve these defects and propose initiating orthodontic tooth movement (OTM) once periodontal therapy goals have been met. Surgical interventions using various regenerative technologies like barrier membranes and enamel matrix proteins, combined or not with bone replacement grafts, have proven effective in regenerating lost periodontal tissues. However, the combination of periodontal and orthodontic treatments requires consideration of how periodontal regenerative therapies influence OTM. Studies suggest that regenerated bone may differ in density, composition, vascularity, and cellular activity, potentially affecting the speed and efficiency of OTM, and potential root resorption of moved teeth. Understanding the sequence and timing of implementing OTM after regenerative periodontal interventions is crucial due to their interlinked processes of bone resorption and formation. This narrative review aims to uncover scientific evidence regarding these combined treatments, examining the impacts of different regenerative technologies on OTM and delineating their advantages, limitations, and best practices.

Stabilization Control of line of sight of OTM(On-The-Move) Antenna (OTM 단말기 안테나 시선 안정화 제어)

  • Kang, Min-Sig;Cho, Yong-Wan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.11
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    • pp.2073-2082
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    • 2010
  • The 4-th generation of mobile communication aims to realize global, fast and mobile communication service. The satellite communication charges a key role in this field. In this study, an OTM(On-The-Move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite was addressed. Since vehicles move during communication, active antenna line-of-sight stabilization is a core technology to guarantee high satellite communication quality. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. Various disturbance torques such as static and dynamic mass imbalance torques, variation of moment of inertia according to elevation angle, friction torque related to vehicle motion, equivalent disturbance torque due to antenna roll motion, etc. were analyzed. As a robust stabilization control, rate feedback with sliding mode control and position feedback with proportional+integral control was suggested. To compensate antenna roll motion, a supplementary roll rate feed forward control was included beside of the feedback control loop. The feasibility of the analysis and the proposed control design were verified along with some simulation results.

Double-Input Singe-Output Architecture of LNA and Correction Method of Phase Variation for OTM Satellite Communication System (OTM(On-The-Move) 위성 통신 시스템을 위한 저잡음 증폭기 출력채널 단일화 구조 및 위상보정 방안)

  • Kwon, Kun-Sup;Ryu, Heung-Gyoon;Heo, Jong-Wan;Hwang, Ki-Min;Jang, Myung-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.1
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    • pp.1-8
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    • 2015
  • In this paper, a double-input single-output architecture of a LNA(Low Noise Amplifier) is presented to enable to be devised for light weight and small-sized OTM(On-The-Move) satellite communication system suitable to be mounted on vehicles. In spite of advantages of the double-input single-output architecture of a LNA such as reduction of the number of physical channels, it results in time-varying phase error between a fundamental mode path and a high-order mode path. This paper shows that the error can be corrected by adding pilot signals to the LNA and using signal processing, and also gives the measurement data to use the method mentioned above.

Effect of nicotine on orthodontic tooth movement and bone remodeling in rats

  • Lee, Sung-Hee;Cha, Jung-Yul;Choi, Sung-Hwan;Kim, Baek-il;Cha, Jae-Kook;Hwang, Chung-Ju
    • The korean journal of orthodontics
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    • v.51 no.4
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    • pp.282-292
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    • 2021
  • Objective: To quantitatively analyze the effect of nicotine on orthodontic tooth movement (OTM) and bone remodeling in rats using micro-computed tomography and tartrate-resistant acid phosphatase immunostaining. Methods: Thirty-nine adult male Sprague-Dawley rats were randomized into three groups: group A, 0.5 mL normal saline (n = 9, 3 per 3, 7, and 14 days); group B, 0.83 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days); and group C, 1.67 mg/kg nicotine (n = 15, 5 per 3, 7, and 14 days). Each animal received daily intraperitoneal injections of nicotine/saline from the day of insertion of identical 30-g orthodontic force delivery systems. A 5-mm nickel-titanium closed-coil spring was applied between the left maxillary first molar (M1) and the two splinted incisors. The rate of OTM and volumetric bone changes were measured using micro-computed tomography. Osteoclasts were counted on the mesial alveolar bone surface of the distobuccal root of M1. Six dependent outcome variables, including the intermolar distance, bone volume fraction, bone mineral density, trabecular thickness, trabecular volume, and osteoclast number, were summarized using simple descriptive statistics. Nonparametric Kruskal-Wallis tests were used to evaluate differences among groups at 3, 7, and 14 days of OTM. Results: All six dependent outcome variables showed no statistically significant among group-differences at 3, 7, and 14 days. Conclusions: The findings of this study suggest that nicotine does not affect OTM and bone remodeling, although fluctuations during the different stages of OTM in the nicotine groups should be elucidated in further prospective studies.