• Journal of Institute of Control, Robotics and Systems
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• v.13 no.8
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• pp.735-742
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• 2007

The importance of the interaction capability of a robot increases as the application of a robot is extended to a human's daily life. In this paper, a portable mediate interface Handybot is developed with various interaction channels to be used with an intelligent home service robot. The Handybot has a task-oriented channel of an icon language as well as a verbal interface. It also has an emotional interaction channel that recognizes a user's emotional state from facial expression and speech, transmits that state to the robot, and expresses the robot's emotional state to the user. It is expected that the Handybot will reduce spatial problems that may exist in human-robot interactions, propose a new interaction method, and help creating rich and continuous interactions between human users and robots.

• Smart Structures and Systems
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• v.8 no.1
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• pp.39-52
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• 2011

We are developing a biomimetic robot based on the Sea Lamprey. The robot consists of a cylindrical electronics bay propelled by an undulatory body axis. Shape memory alloy (SMA) actuators generate propagating flexion waves in five undulatory segments of a polyurethane strip. The behavior of the robot is controlled by an electronic nervous system (ENS) composed of networks of discrete-time map-based neurons and synapses that execute on a digital signal processing chip. Motor neuron action potentials gate power transistors that apply current to the SMA actuators. The ENS consists of a set of segmental central pattern generators (CPGs), modulated by layered command and coordinating neuron networks, that integrate input from exteroceptive sensors including a compass, accelerometers, inclinometers and a short baseline sonar array (SBA). The CPGs instantiate the 3-element hemi-segmental network model established from physiological studies. Anterior and posterior propagating pathways between CPGs mediate intersegmental coordination to generate flexion waves for forward and backward swimming. The command network mediates layered exteroceptive reflexes for homing, primary orientation, and impediment compensation. The SBA allows homing on a sonar beacon by indicating deviations in azimuth and inclination. Inclinometers actuate a bending segment between the hull and undulator to allow climb and dive. Accelerometers can distinguish collisions from impediment to allow compensatory reflexes. Modulatory commands mediate speed control and turning. A SBA communications interface is being developed to allow supervised reactive autonomy.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.920-926
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• 2007

새로운 매체와 접촉 시 발생하는 거부감을 최소화 하고 별도의 학습 없이 사용 가능한 직관적 명령 전달 방식의 매개 인터페이스를 제안한다. 제안하는 매개 인터페이스는 3차원 공간에서 사용가능한 가상 마우스와 TV 리모트 컨트롤러의 기능적 결합을 목표로 하고 실버세대들에게 익숙한 매체인 펜을 형태로 삼아 개념적으로 설계되었다. 구체적인 구현은 가속도계의 신호를 분석하거나 펜촉에 레이저 포인터를 추가하여 레이저 포인터의 좌표 변화를 웹캠으로 추적, 인식하는 방법으로 구분하였고 본 논문에서는 가속도계의 경우를 소개한다. 가속도계 신호분석을 통해 마우스의 기능을 모사하고 동작을 감지하는데 발생하는 문제점과 이를 해결하기 위한 기존 연구를 분석하고 동작 중에 중력방향의 수직축이 바뀌면서 발생하는 가속도계 신호의 오류를 보상하기 위해 제안된 Zero Velocity Compensation 방법을 소개한다. ZVC의 결과에 필수적인 저주파의 시계열 신호 실시간 끝점 추출과 동시에 패턴인식을 위한 특징추출 기능을 수행하는 새로운 알고리즘을 제안하며 기존의 방법과 실험적으로 성능을 비교한다. 또한 입력된 가속도계 신호를 학습된 인식기를 통해 인식하는 기존의 연구에서 더 나아가, 마우스의 좌표변화를 짧은 시간동안 가속도 신호의 실시간 분석을 통해 모사하기 위해 변형시킨 알고리즘을 소개한다.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2001.06a
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• pp.27-31
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• 2001

Previous biochemical assays and a structural model indicated that the dimer interface of the Hin recombinase is composed of the two a-helices. To elucidate the structure and function of the helix, amino acids in the N-terminal end of the helix, where the two helices contact most, were randomized, and inversion-incompetent mutants were selected. To investigate why the mutants lost their inversion activities, the DNA binding, hix-pairing, invertasome formation, and DNA cleavage activities were assayed using in vivo and in vitro methodologies. Results indicated that the mutants could be divided into 4 classes based on their DNA binding activity. We proposed that the a-helices might place a DNA binding motif of Hin properly to the minor DNA groove of the recombination site. All the mutants except the non-binders were able to perform hix-pairing and invertasome formation, suggesting that the dimer interface is not involved in the process of hix-pairing or invertasome formation. The inversion-incompetent phenotype of the binders was caused by the inability of mutants to perform the DNA cleavage activity. The less binders exhibited wild-type level of hix-pairing activity because the hix-pairing activity overcomes the DNA binding defect of the less binders. This phenotype of the less binders suggests that the binding domains of Hin could mediate Hin-Hin interaction during hix-pairing..

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.53.2-53.2
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• 2011

Ti metal has superior mechanical properties along with biocompatibility, but it still has the problem of bio-inertness thus forming weaker bond in bone/implant interface and long term clinical performance as orthopaedic and dental devices are restricted for stress shielding effect. On the other hand, despite the excellent biodegradable behavior as being an integral constituent of the natural bone, the mechanical properties of ${\beta}$-tricalcium phosphate $(Ca_3(PO_4)_2;\;{\beta}-TCP)$ ceramics are not reliable enough for post operative load bearing application in human hard tissue defect site. One reasonable approach would be to mediate the features of the two by making a composite. In this study, ${\beta}$-TCP/Ti ceramic-metal composites were fabricated by spark plasma sintering in inert atmosphere to inhibit the formation of $TiO_2$. Composites of 30 vol%, 50 vol% and 70 vol% ${\beta}$-TCP with Ti were fabricated. Detailed microstructural and phase characteristics were investigated by FE-SEM, EDS and XRD. Material properties like relative density, hardness, compressive strength, elastic modulus etc. were characterized. Cell viability and biocompatibility were investigated using the MTT assay and by examining cell proliferation behavior.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.476-476
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• 2011

Introduction of CNTs into a metal matrix has been considered to improve the mechanical properties of the metal matrix. However, the binding energy between metals and pristine CNTs wall is known to be so small that the interfacial slip between CNTs and the matrix occurs at a relatively low external stress. The interfacial strength between CNT and metal matrix is thus one of the key factors for successful development of the CNT/metal composites. Defective or functionalized CNT has been considered to enhance the interfacial strength of nanocomposites. In the present work, we design the various realistic hybrid structures of the single wall CNT/Cu complexes and characterize the interaction between single wall CNTs and Cu nano-particle and Cu13 cluster using first principle calculations. The characteristics of functionalized CNTs with various surface functional groups, such as -COOH, -OH, and -O interacting with Cu are investigated. We found that the binding energy can be enhanced by the surface functional group including oxygen since the oxygen atom can mediate and reinforce the interaction between carbon and Cu. These results strongly support the recent experimental work which suggested the oxygen on the interface playing an important role in the excellent mechanical properties of the CNT/Cu composite.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.61-61
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• 2010

In the present work, we present the optimized the hybrid structures of carbon nanotubes (CNTs) and metal nanocomposites including Cu, Al, Co and Ni using the first principle calculations based on the density functional theory. Introduction of CNTs into a metal matrix has been considered to improve the mechanical properties of the metal matrix. However, the binding energy between metals and pristine CNTs wall is known to be so small that the interfacial slip between CNTs and the matrix occurs at a relatively low external stress. The application of defective or functionalized CNTs has thus attracted great attention to enhance the interfacial strength of CNT/metal nanocomposites. Herein, we design the various hybrid structures of the single wall CNT/metal complexes and characterize the interaction between single wall CNTs and various metals such as Cu, Al, Co or Ni. First, differences in the binding energies or electronic structures of the CNT/metal complexes with the topological defects, such as the Stone-Wales and vacancy, are compared. Second, the characteristics of functionalized CNTs with various surface functional groups, such as -O, -COOH, -OH interacting with metals are investigated.We found that the binding energy can be enhanced by the surface functional group including oxygen since the oxygen atom can mediate and reinforce the interaction between carbon and metal. The binding energy is also greatly increased when it is absorbed on the defects of CNTs. These results strongly support the recent experimental work which suggested the oxygen on the interface playing an important role in the excellent mechanical properties of the CNT-Cu composite[1].

• Journal of Digital Convergence
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• v.14 no.1
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• pp.285-290
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• 2016

To identify virtual reality (VR) interventions used for upper extremity rehabilitation in stroke patients. The Medline database was searched up to February 11, 2015. Randomized controlled and clinical trials that included a VR intervention for upper extremity rehabilitation in stroke patients were included. The Physiotherapy Evidence Database (PEDro) scale was used to assess the quality of the included studies. In total, 8 studies were included. PEDro scores varied from 5 to 8/10. All studies showed significant improvement in outcomes in favor of the VR group. This review suggests that VR applications used for upper extremity rehabilitation in stroke patients predominantly mediate learning through providing task-oriented and graduated learning with variable and unpredictable practice.

• The KIPS Transactions:PartD
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• v.15D no.5
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• pp.659-668
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• 2008

Recently, the component model based on the Exogenous Connector has been proposed in which controls are separated from computation by managing the beginning and result of method calls in the connector. Although it could be loosely coupled between components, it has a problem that is a potential preponderance of element objects of the system by increasing the number of connectors and connection levels. In this paper we propose the Tree Component Model with the Hybrid Message Passing that combines direct and indirect message passing. In our model, components are wrapped by interfaces and controls are separated from computation by only using their interface references. There is a unique feature that the composition structure of components becomes the tree always. As a result of demonstration and comparison, it is found that the Tree Component Model is applicable practically and decreases objects to mediate message passing and build the system.

• Journal of Internet Computing and Services
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• v.21 no.3
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• pp.1-9
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• 2020

Along with the growth of Blockchain, DApp (Distributed Application) is getting attention. As interest in DApp grows, market size continues to grow and many developers participate in development. Many developers are using API(Application Programming Interface) services to mediate Blockchain nodes, such as Infura, for DApp development. However, when using such a service, there is a serious risk that the API service operator can violate the user's privacy by 1 to 1 matching the account address of the Transaction executed by the DApp user with the IP address of the DApp user. It can have an adverse effect on the reliability of public Blockchains that need to provide users with a secure DApp service environment. The proposed Blockchain platform is expected to provide user privacy protection from API services and provide a reliable DApp use environment that existing Blockchain platforms did not provide. It is also expected to help to activate DApp and increase the number of DApp users, which has not been activated due to the risk of an existing privacy breach.