3,147 research outputs found
절첩식 성장유닛을 포함하는 성장형 소프트로봇
No full textA growth-type soft robot includes a housing including an external body including an internal accommodation space and one side open and a fixing portion formed on a periphery of an open region of the external body, a growth unit including an outer periphery having one end connected to the fixing portion, an inner periphery spaced apart from an inner side of the outer periphery and extending to the accommodation space, and a bent portion connecting the other end of the outer periphery to one end of the inner periphery to form a front end space, and a data collecting unit including a cable extending along a central portion surrounded by the inner periphery and a sensing module acquiring external information, wherein the other end of the inner periphery forms a folded region, and a length of the growth unit is adjustable by air supplied to the front end space
Sobolev regularity theory for the non-local elliptic and parabolic equations on open sets
No full textWe study the zero exterior problem for the elliptic equation Delta alpha/2u - lambda u = f, x E D ; u|Dc =0 as well as for the parabolic equation ut = Delta alpha/2u + f, t > 0, xED; u(0,')|D= u0, u|[0,T]xDc = 0. Here, alpha E (0, 2), lambda > 0 and D is a C',' open set. We prove uniqueness and existence of solutions in weighted Sobolev spaces, and obtain global Sobolev and Ho center dot lder estimates of solutions and their arbitrary order derivatives. We measure the Sobolev and Ho center dot lder regularities of solutions and their arbitrary derivatives using a system of weights consisting of appropriate powers of the distance to the boundary. The range of admissible powers of the distance to the boundary is sharp.
Temporal partitioning to amortize reconfiguration overhead for dynamically reconfigurable architectures
No full textIn these days, many dynamically reconfigurable architectures have been introduced to fill the gap between ASICs and software-programmed processors such as GPPs and DSPs. These reconfigurable architectures have shown to achieve higher performance compared to software-programmed processors. However, reconfigurable architectures suffer from a significant reconfiguration overhead and a speedup limitation. By reducing the reconfiguration overhead, the overall performance of reconfigurable architectures can be improved. Therefore, we will describe temporal partitioning, which are able to amortize the reconfiguration overhead at synthesis phase or compilation time. Our temporal partitioning methodology splits a configuration context into temporal partitions to amortize reconfiguration overhead. And then, we will present benchmark results to demonstrate the effectiveness of our methodology
A new chaotic attractor and its robust function projective synchronization
No full textWe introduce a simple chaotic system that contains one multiplier and one quadratic term. The system is similar to the generalized Lorenz system but is not topologically equivalent. The properties of the proposed chaotic system are examined by theoretical and numerical analysis. An analog chaotic circuit is implemented that realizes the chaotic system for the verification of its attractor. Furthermore, we propose a robust function projective synchronization using time delay estimation. A numerical simulation of synchronization between the proposed system and the Lorenz system demonstrates that the proposed approach provides fast and robust synchronization even in the presence of unknown parameter variations and disturbances. © 2013 Springer Science+Business Media Dordrecht
Early union of grafted bone in ankylosing spondylitis: comparative study with degenerative spinal disease.
No full textPatients with ankylosing spondylitis (AS) achieve early bone union compared to those with other spinal diseases. This study compared the time to bone union after surgery between AS patients and degenerative spinal disease patients. Patients with degenerative spinal diseases (control group) and AS (experimental group) underwent pedicle subtraction osteotomy followed by posterolateral fusion, and decompression and posterolateral fusion, respectively. There were 10 patients in the experimental group. The control group included 26 patients who were less than 50 years of age and underwent two-level autogenous grafting after decompression and spinal fusion. Autogenous grafts and a range of bone substitutes were used in the experimental group, whereas only autogenous grafts were used in the control group. Bone union was determined on the radiographs and 3-dimensional CT scan images. The level of union was assessed using the Lenke's and Christensen's classification systems. In the experimental group, the mean age was 41.3 years (range, 30 to 67 years), the mean follow-up period was 21.7 months (range, 12 to 43 months), and bone union was confirmed at an average of 3.5 months (range, 3 to 5 months) after surgery. In the control group, the mean age was 43.1 years (range, 35 to 50 years), the mean follow-up period was 21.8 months (range, 12 to 74 months), and bone union was observed at an average of 5.6 months (range, 4 to 12 months) after surgery. The difference in the time to bone union between the two groups was significant (p = 0.023). The union of grafted bone was obtained earlier in patients with AS than in those with degenerative spinal diseases. Therefore, future studies should examine the factors affecting the early union in AS patients
sj-docx-1-tan-10.1177_17562864231218181 – Supplemental material for Effect of altered gene expression in lipid metabolism on cognitive improvement in patients with Alzheimer’s dementia following fecal microbiota transplantation: a preliminary study
No full textSupplemental material, sj-docx-1-tan-10.1177_17562864231218181 for Effect of altered gene expression in lipid metabolism on cognitive improvement in patients with Alzheimer’s dementia following fecal microbiota transplantation: a preliminary study by Jun-Seob Kim, Hyelim Park, Jung-Hwan Lee, Jongbeom Shin, Boram Cha, Kye Sook Kwon, Yong Woon Shin, Yerim Kim, YeoJin Kim, Jong Seok Bae, Ju-Hun Lee, Seok-Jin Choi, Tae Jung Kim, Sang-Bae Ko and Soo-Hyun Park in Therapeutic Advances in Neurological Disorders</p
A 120 GHz Wideband CMOS I/Q Transmitter for Short-Range Wireless Device-to-Device Communication
No full textIn this paper, we present a 120 GHz CMOS I/Q transmitter for short-range wireless device-to-device communication. Targeting 16-QAM communication at a transmission distance of 10 cm, an I/Q transmitter with an injection-locked frequency tripler chain (ILFT) having a data transfer rate oftens of Gbps is designed. To minimize the image-rejection ratio (IMRR) and enhance the EVM performance, the I/Q gain and phase calibration circuits are also integrated in the ILFT. In the simulation, our proposed transmitter exhibits wideband characteristics over 25 GHz and 14.7 dB conversion gain. From the I/Q calibration, the transmitter shows a high IMRR over 50 dBc
Impedance control of robot manipulator using nonlinear impedance model with finite time convergence characteristics
No full text학위논문(석사) - 한국과학기술원 : 기계공학전공, 2011.2, [ vi, 88 p. ]본 논문은 유한시간 수렴특성을 가지는 비선형 임피던스 모델을 이용한 로봇 매니퓰레이터의 임피던스 제어를 다룬다. 임피던스 모델은 임피던스 제어에서 중요한 부분이다. 그러나 지금까지 임피던스 제어에서는 분석과 설계상의 용이성 때문에, 선형 질량-감쇠기-스프링 모델이 사용되었다. 따라서, 본 논문에서는 궤적추종성능과 안정적 접촉 움직임을 보장하는 비선형 임피던스 모델을 제안하고자 한다. 제안한 모델은 유한시간 수렴특성을 가질 뿐 아니라 선형 임피던스 모델을 모두 포함하며, 페이즈 플롯에서의 분석을 통해 환경과의 접촉상황에서의 안정적 접촉이 가능함을 확인하였다. 더하여 제안한 모델의 설계가이드라인을 제공하여 실제 사용에 있어 편의를 도모하였다. 더하여 제안한 모델을 로봇에 적용하기 위하여 시간지연제어(Time Delay Control)을 이용하였다. 그리고 궤적추종성능의 향상과 안정적인 접촉움직임을 검증하기 위하여 산업용 로봇을 이용하여 1자유도 및 2자유도 임피던스 제어 실험을 수행하였다. 마지막으로, 실험을 통하여 선형 모델과 비교한 결과를 살펴보면, 제안한 임피던스 모델은 궤적추종성능이 향상될 뿐 아니라, 환경과 접촉시 안정적 작업수행이 가능함을 확인할 수 있다.한국과학기술원 : 기계공학전공
A Sequential Search Method of Dispatching Rules for Scheduling of LCD Manufacturing Systems
No full textA combination of dispatching rules to determine a sequence of jobs is often used for the scheduling of liquid crystal display or semiconductor manufacturing systems. Fab engineers determine weights ranging between 0 and 1 for dispatching rules, and the dispatching rules assign a value from 0 to 1 for each job. Then the weight given by the engineers and the value from each dispatching rule are multiplied and added for all rules, and the job that has the largest weighted sum is chosen to be processed on an idle machine. Hence, the weights of dispatching rules significantly affect the performance of fabs and should be determined carefully. This article proposes a sequential search method for finding a proper set of weights for dispatching rules to improve an objective value of the fab, such as increasing throughput or decreasing setup times. We use a decision tree approach and a hierarchical clustering method to efficiently search for weights in a short period of time by eliminating some sub-spaces that are less likely to have good objective values. The proposed method finds better weight sets than a random search method and a response optimization method in experiments.
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