• The KIPS Transactions:PartC
• /
• v.9C no.1
• /
• pp.97-106
• /
• 2002

In 3GPP2 standard, MIP is used and a PDSN performs the function of FA to support macro mobility. When a MS is roaming from a PDSN area to another, the mobility supported is called macro mobility, while it is called micro mobility when a MS is roaming from a RN area to another in a PDSN area. Since a PDSN performs the function of FA in 3GPP2 standard, it is possible to support mobility but its mechanism is actually for supporting macro mobility, not for micro mobility, thus it is weak in processing fast and seamless handoff to support micro mobility. In this paper, we suggest the seamless handoff algorithm barred on multicast group mechanism to support micro mobility. Depending on the moving direction and velocity of a MS, the suggested algorithm constructs a multicast group of RNs on the forecasted MS's moving path, and maximally delays RNs'joining to a multicast group to increase the network efficiency. Moreover, to resolve the buffer overhead problem of the existent multicast scheme, the algorithm suggests that each RN buffers data only after the forecasted handoff time. To prove deadlock freeness and liveness of the algorithm. we use state transition diagrams, a Petri-net modeling and its reachability tree. Then, we evaluate the performance by simulation.

• Journal of Korean Society of Neurocognitive Rehabilitation
• /
• v.10 no.2
• /
• pp.27-34
• /
• 2018

The purpose of this study is to investigate the effect of task training for cognitive activation of upper extremity on upper limb function and activities of daily living and to suggest intervention in rehabilitation treatment. From January to February of 2018, nine stroke patients were arbitrated 30 minutes a day, five days a week, for four weeks. For the experimental group, the therapist has induced the group using the linguistic guidance to patients, so they utilize the cognition strategy. The control group conducted active exercises in a range of motion using the instruments and passive exercises in a range of motion to reduce the stiffness of joints and upper limbs. As muscle strengthening exercises, the patients were assigned to work on the biceps muscle of arm, triceps muscle of arm, and deltoid according to the individual patient's muscular strength level. For the experimental group, the MBI was improved by ten points at maximum, and K-AMPS motor skills showed the improvements of 1.0 logit at maximum, and processing skills showed improvements of 0.6 logits at maximum. In MFT, the maximum improvement was by two points. For the control group, MBI was improved by five points at maximum, and 0.2 maximum improvements were shown in K-AMPS' motor skills and 0.3 maximum improvements in processing skills. MFT showed no change. The conclusion is that the challenges to enable training for stroke patients give a positive impact on upper limb function and activities of daily living.

• The Journal of Korean Academy of Prosthodontics
• /
• v.45 no.5
• /
• pp.589-600
• /
• 2007

Statement of Problem: Titanium has many advantages of high biocompatibility, physical porperties, low-weight, low price and radiolucency, but it is incompatible with conventional dental porcelain due to titanium's oxidative nature. Many previous studies have shown that they used the method of sandblast surface treatment prior to porcelain application, the researchs are processing about the method of acid etching or surface coating. Purpose: The purpose of this research is to study the effect on bond strength between titanium and porcelain when using macro-surface treatment and micro-surface treatment and macro and micro surface treatment. Material and method: In this study, we evaluated the bond strength by using 3-point bending test based on ISO 9693 after classified 7 groups-group P : polished with #1200 grit SiC paper, group SS : sandblasted with $50{\mu}m$ aluminum oxides, group LS : sandblasted with $250{\mu}m$ alumium oxides, group HC : treated with 10% hydrochloric acid, group NF : treated with 17% solution of fluoric acid and nitric acid, group SHC : treated with 10% hydrochloric aicd after sandblsting with $50{\mu}m$ alumium oxides, group SNF treated with 17% solution of fluoric acid and nitric acid. Results : Within the confines of our research, the following results can be deduced. 1. Group SS which was sandblasted with $50{\mu}m$ aluminum oxides showed the highest bond strength of 61.74 MPa and significant differences(P<0.05). The bond strengths with porcelain in groups treated acid etching after sandblasting decreased more preferable than the group treated with sandblasting only. It gives significant differences(P<0.05). 2. After surface treatments, the group treated with sandblasting showed irregular aspect formed many undercuts, in the SEM photographs. The group treated with hydrochloric acid had the sharp serrated surfaces, the group treated with the solution of fluoric acid and nitric acid had the smooth surfaces, the group with sandblasting and hydrochloric acid had irrigular and porous structure, the group with sandblasting and the solution of fluoric acid and nitric acid had crater-like surfaces. But all of the groups treated with acid etching was not found and undercut. Conclusion: In above results, average surface roughness increase, bond strength also increase, but surface topographs influences more greatly on bond strengths.

• Journal of the Institute of Convergence Signal Processing
• /
• v.2 no.3
• /
• pp.1-8
• /
• 2001

In this paper, we proposed the automatical recognition algorithm of bar-code using a vision system, which can be used in the industrial application(code 93). The proposed algorithm extracts the pixels which consist of the bar-code modules unrelated to rotation, then that obtains the elements which consist of bars and spaces. After the obtained elements are divided by nine group, the value of bar-code is recognized. The performance of proposed algorithm is verified through the simulation. The proposed one has good performance.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1826-1828
• /
• 2004

In this paper, we present an ultrasonic velocity and attenuation measurement system. There are many ultrasonic measurement methods that are used in nondestructive testing applications. They include material property determination, microstructural characterization, and flaw detection. Ultrasonic parameters such as velocity and attenuation are most commonly used in them. Advanced signal analysis which is called "ime-frequency analysis"has been used widely in nondestructive evaluation applications. Wavelet transform is the most advanced technique for processing signals with time-varying spectra. Using the echo waveform gathered by the designed hardware system, we performed simulation of the signal processing algorithms. Then the algorithm is implemented on the system.

• Journal of Information Processing Systems
• /
• v.13 no.3
• /
• pp.491-499
• /
• 2017

In this study, we proposed a new approach to segment ground and nonground points gained from a 3D laser range sensor. The primary aim of this research was to provide a fast and effective method for ground segmentation. In each frame, we divide the point cloud into small groups. All threshold points and start-ground points in each group are then analyzed. To determine threshold points we depend on three features: gradient, lost threshold points, and abnormalities in the distance between the sensor and a particular threshold point. After a threshold point is determined, a start-ground point is then identified by considering the height difference between two consecutive points. All points from a start-ground point to the next threshold point are ground points. Other points are nonground. This process is then repeated until all points are labelled.

• Journal of Information Processing Systems
• /
• v.12 no.2
• /
• pp.226-233
• /
• 2016

Cloud computing is a distributed computing model that has lot of drawbacks and faces difficulties. Many new innovative and emerging techniques take advantage of its features. In this paper, we explore the security threats to and Risk Assessments for cloud computing, attack mitigation frameworks, and the risk-based dynamic access control for cloud computing. Common security threats to cloud computing have been explored and these threats are addressed through acceptable measures via governance and effective risk management using a tailored Security Risk Approach. Most existing Threat and Risk Assessment (TRA) schemes for cloud services use a converse thinking approach to develop theoretical solutions for minimizing the risk of security breaches at a minimal cost. In our study, we propose an improved Attack-Defense Tree mechanism designated as iADTree, for solving the TRA problem in cloud computing environments.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.05a
• /
• pp.983-986
• /
• 2006

Self-healing 키 분배 방법은 불안정한 채널에서 규모가 크고 동적인 그룹에 적합하다. 제한된 전력과 컴퓨팅 능력을 가진 다수의 노드들을 기반으로 하는 센서네트워크 환경에서 self-healing 키 분배 방법은 효율적인 키 분배를 제공할 수 있는 접근법이다. 더불어 local collaboration은 같은 그룹에 속한 노드들이 서로 협력하여 그룹 키를 보호하고 침입자에 의해 손상된 노드를 발견할 수 있는 유용한 방법이다. 본 논문에서는 기존의 self-healing 키 분배 방법을 보완하여 센서네트워크 환경에 적용하기 위하여 임의의 변수를 적용한 지역적 협력(local collaboration)을 사용한다. 결과적으로 그룹 단위로 키를 안전하게 분배 및 관리를 할 수 있으며 센서 노드들 간의 통신비용 및 메모리에 대한 효율성 향상을 가져올 수 있음을 실험을 통하여 검증한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.05a
• /
• pp.995-998
• /
• 2006

IGMP(Internet Group Management Protocol)는 멀티캐스트 그룹의 멤버쉽 관리를 위한 프로토콜로서, 임의의 호스트가 멀티캐스트 라우터에게 특정한 멀티캐스트 통신의 수신을 요청할 경우에 사용된다. 본 논문에서는 이와 같은 IGMP 메시지를 이용한 정당하지 않은 호스트의 DoS 공격 등으로부터 멀티캐스트 분배트리의 보호를 위한 수신자 접근제어 기법을 제안한다. 또한 제안기법은 수신자 접근제어 기능뿐만 아니라, 실제 다양한 상업적인 멀티캐스트 서비스에도 적용될 수 있는 비즈니스 모델을 기반으로 하며 과금과 관련하여 활용이 가능하다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.05a
• /
• pp.1325-1328
• /
• 2006

본 논문에서는 RTOS 기반 임베디드 소프트웨어 개발에 적합한 모델기반 방법론을 제안하고 이와 함께 개발된 자동코드생성 도구를 기술한다. 현재까지 알려진 대표적인 모델기반 방법론으로는 OMG (Object Management Group)의 MDA (Model-Driven Architecture)가 있으며, MDA 에서는 EJB, 웹서비스,.NET, 그리고 CORBA 와 같은 미들웨어 플랫폼을 대상으로 하는 응용 소프트웨어의 개발을 지원한다. 하지만, 통상적인 임베디드 시스템은 실시간성에 대한 요구조건은 물론 성능과 자원활용에 있어 많은 제약을 가짐에 따라 상당수의 임베디드 시스템은 미들웨어를 사용하지 않고 RTOS 상에서 직접 수행되도록 개발되고 있다. 이에 따라 본 연구에서는 MDA 방법론을 확장하여 플랫폼 의존적인 모델 (PSM, Platform Specific Model) 단계에서 추상화된 RTOS 행위를 표현할 수 있도록 추상 RTOS API (Generic RTOS API)를 정의하고, 아울러 추상화된 RTOS 행위를 자동으로 변환하여 C 코드를 생성해주는 도구인 TransPI 를 함께 제시한다.