• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.111-112
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• 2014

This research focuses on the study that micro-crack of concrete is repaired to use self-healing technology. Self-healing concrete is widely studied in domestic and international construction field recently. Micro-crack(less than 0.3mm)of concrete is repaired using a crack repair stick which containing self-healing agents. Therefore, the crack on construction structure will be easily repaired by using a crack repair stick. Also experiment was proceeded because of evaluating the long term durability.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.758-759
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• 2011

• 한국CDE학회지
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• 제21권2호
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• pp.65-68
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• 2015

Creative selfie stick design using FreeCAD and Ansys.

• 한국소음진동공학회논문집
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• 제22권8호
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• pp.748-755
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• 2012

Friction causes self-excited vibration, stick-slip vibration and any other friction-induced phenomena. That kinds of vibrations cause chatter and squeal. In order to predict such vibrations accurately, employing an accurate friction model is very important because a dynamic behavior of a system with friction is dominantly governed by a friction model. A Coulomb friction model is the most widely known model. Coulomb friction model is useful model to obtain analytical solutions of the system with friction and the model gives relatively good simulation result. However, defining a friction force at a stick state in simulation is hard because of the characteristic itself and a Coulomb friction model is discontinuous function between a static and a dynamic friction coefficient. Therefore, applying the Coulomb friction model to a simulation is not appropriate. In order to resolve these problems, an approximated Coulomb friction model was developed using simple and continuous function. However, an approximated Coulomb friction model cannot realize stick. Therefore, an approximated Coulomb friction model cannot describe friction phenomena accurately. In order to analyze a friction phenomenon accurately, a friction model for a simulation was proposed in this paper. A proposed friction model realizes stick and gives reasonably good results compared to results obtained by the simulation employing an approximated Coulomb friction model. Accuracy of a proposed friction model was verified by comparing experimental results.

• Tribology and Lubricants
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• 제31권1호
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• pp.6-12
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• 2015

This paper investigates the stick-slip characteristic of magnetorheological elastomer (MRE) between an aluminum plate and the surface of the MRE. MRE is a smart material and it can change its mechanical behavior with the interior iron particles under the influence of an applied magnetic field. Stick-slip is a movement of two surfaces relative to each other that proceeds as a series of jerks caused by alternate sticking from friction and sliding when the friction is overcome by an applied force. This special tribology phenomenon can lead to unnecessary wear, vibration, noise, and reduced service life of work piece. The stick-slip phenomenon is avoided as far as possible in the field of mechanical engineering. As this phenomenon is a function of material property, applied load, and velocity, it can be controlled using the characteristics of MRE. MRE as a soft smart material, whose mechanical properties such as modulus and stiffness can be changed via the strength of an external magnetic field, has been widely studied as a prospective replacement for general rubber in the mechanical domain. In this study, friction force is measured under different loads, speed, and magnetic field strength. From the test results, it is confirmed that the stick-slip phenomenon can be minimized under optimum conditions and can be applied in various mechanical components.

• 대한치과기공학회지
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• 제42권2호
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• pp.91-98
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• 2020

Purpose: This study is to compare the flexural strength and modulus by inserting a mesh and stick type fiberglass reinforcement into resin specimens. Methods: Wax specimens (length 64 mm, width 39 mm, thickness 5 mm) are prepared according to ISO 20795-1:2013. Mesh type and stick type glass fiber reinforcements were prepared. The prepared wax specimens were used plaster and flask for investment. The flask was separated and the wax was removed. The heat curing resin was injected into the flask, and then a mesh type and stick type fiberglass reinforcement were inserted. The prepared resin specimen was cut into three equal parts (length 64 mm, width 10 mm, thickness 3.3 mm). The mesh type glass fiber reinforcement (MT group) and the stick type glass fiber reinforcement (ST group) were classified into two groups. The prepared specimen was measured using a universal testing machine (UTM). The data were analyzed by Mann-Whitney U test, and the significance level was set to 0.05. Results: In the flexural strength, the ST group was higher than the MT group, and there was a significant difference between the two groups (p<0.05). In the flexural modulus, the ST group was higher than the MT group, and there was a significant difference between the two groups (p<0.05). Conclusion: The stick-type glass fiber inreased the flexural strength than the mesh-type glass fiber reinforcement.

• 한국통신학회논문지
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• 제36권3B호
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• pp.287-296
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• 2011

시각장애인들이 주로 사용하고 있는 백색 지팡이(White Stick)는 지상의 부유장애물에 대한 감지가 어려울 뿐만 아니라, 보행중인 시각장애인에게 현재 위치정보와 응급상황 발생시 효과적인 보호 조치를 제공하는데 문제점이 있다. 본 논문에서는 이와 같은 문제점을 해결하여 시각장애인들이 보다 안전하고 편리한 보행을 할수 있는 사물지능통신(M2M : Machine-to-Machine) 기반의 지능형 보행보조시스템을 제안한다. 제안하는 시스템은 시각장애인이 사용하는 보행보조지팡이와 이동통신망을 통하여 다수의 보행보조지팡이 사용자를 원격 지원하는 서버로 구성된다. 보행보조지팡이는 초음파센서와 문자-음성 변환기술 등을 이용한 장애물 감지 및 인지 가능뿐만 아니라, 서버에서 제공하는 지리정보와 GPS(Global Positioning System) 수신 장치 등을 이용한 현재위치 알림 및 확인, 위급상황 대처 기능 등을 제공한다. 서버는 지리정보 제공뿐만 아니라, 보호자나 구호기관에 위급상황 발생위치 알림, 보행 동안의 주요 정보(장소 시간 및 횟수 등)를 제공한다. 제안 시스템의 시제품을 통한 기능 및 성능 시험 결과 만족스런 결과를 얻을수 있었다.

• 한국전문물리치료학회지
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• 제18권1호
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• pp.57-63
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• 2011

The purpose of this study was to identify the effects of manual facilitation and a stick on lumbar and hip joint flexion angles in subject with lumbar flexion syndrome during forward bending from a sitting position. Fifteen subjects with lumbar flexion syndrome were recruited for this study. As a pretest, all subjects performed three repetitions of bending the trunk forward until the tips of their fingers touched the target bar. After this pretest, the subjects practiced the forward bending of the trunk 10 times, using either manual facilitation or a stick. Then, as a posttest, all subjects repeated the pretest procedure. The flexion angles of lumbar spine and hip joint during forward bending in a sitting position were measured using a three-dimensional motion analysis system. A paired t-test was used to determine the statistical differences between pre-test and post-test flexion angles and pre- and post-test flexion angle differences between forward bending with manual facilitation and forward bending with a stick. The level of statistical significance was set at p=.05. The results of the study showed that the angle of the lumbar flexion decreased significantly and the bilateral hip flexion angle increased significantly when performing forward bending with stick and manual facilitation. Furthermore, the angle of lumbar flexion decreased significantly and the angle of bilateral hip flexion increased significantly in forward bending with a stick compared to forward bending with manual facilitation. The findings of this study indicate that both forward bending with manual facilitation and sticks could be used to prevent excessive lumbar flexion and increase hip flexion, and that forward bending with a stick is more effective than forward bending with manual facilitation for inducing lumbar spine and hip joint angle changes.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1995년도 제47차 추계 학술대회 연제집
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• pp.137-138
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• 1995

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.59-60
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• 2012