• Proceedings of the Korean Society of Disaster Information Conference
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• 2017.11a
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• pp.347-348
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• 2017

헬리컬파일은 한 개 이상의 나선형 원판이 고강도 강관 파이프에 부착된 말뚝이다. 기존의 헬리컬파일은 커플러 형태의 연결방식을 사용하였으나, 볼트 구멍과 볼트사이의 유격 및 연결소켓과 강관 사이의 유격등으로 인한 높은 지지력 기대가 힘들었다. 본 연구는 헬리컬파일 연결방식 개선을 위해 기존 커플러형식에서 플랜지 형식을 적용하였고, 정재하시험을 통해 지지력을 비교 분석 하였다. 정재하시험결과 플랜지 형태의 연결방식이 커플러 형태의 연결방식보다 높은 지지력이 발휘되었고 플랜지형태 적용시 상향식그라우팅이 가능하여 품질이 향상되었다. 또한 연결부 유격을 방지 할 수 있었다.

• Earthquakes and Structures
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• v.16 no.4
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• pp.455-468
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• 2019

The behavior of pile-deck connections of pile-supported marginal wharfs subjected to earthquake loading is of key importance to ensure a good performance of this type of structures. Two precast-pretensioned pile-deck connections used in the construction of pile-supported marginal wharfs were tested under cyclic loading. The first is a connection with simple reinforcement details and light steel ratio developed for use where moderate pile-deck rotation demands are expected in the wharf. The second is specifically developed to sustain the large rotation, shear force and bending moment demands, as required for the shortest piles in a marginal wharf. Data obtained from the test program is used in the paper to calibrate an equivalent plastic hinge length that can be incorporated into nonlinear analysis models of these structures when prestressed pile-deck connections with duct embedded dowels are used.

• Journal of Korean Association for Spatial Structures
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• v.19 no.3
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• pp.61-68
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• 2019

A tensegrity module structure is suitable type for spatial structures. Because the tensegrity is composed of set of discontinuous compressive elements (struts) floating within a net of continuous tensile elements (cables), the system can provide the basis for lightweight and strong. However, despite the advantages of tensegrities, design and fabrication of the systems have difficulty because of form-finding methods, pin-connection and the control of prestress. In this paper, the new pin-connection method was invented to make the tensegrity module. The production process and practical implementation of uniformly compressed the tensegrity structures by using a UTM are described. Experiments showed the mechanical response and failure aspects of the tensegrity system.

• Journal of Biomedical Engineering Research
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• v.30 no.3
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• pp.185-190
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• 2009

Biomedical mobile devices for ubiquitous healthcare consist of biomedical sensors and communication terminal. They have two types of configuration. One is the sensor-network type device using wired or wireless communication with intelligent sensors to acquire biomedical data. The other is the sensor embedded type device, where the data can be acquired directly by itself. There are many examples of sensor network type, such as, fall detection sensor, blood glucose sensor, and ECG sensors networked with commercial PDA phone and commercial phone terminal for ubiquitous healthcare. On the other hand, sensor embedded type mounts blood glucose sensor, accelerometer, and etc. on commercial phone. However, to enable true ubiquitous healthcare, motion sensing is essential, because users go around anywhere and their signals should be measured and monitored, when they are affected by the motion. Therefore, in this paper, two biomedical mobile devices with motion monitoring function were addressed. One is sensor-network type with motion monitoring function, which uses Zigbee communication to measure the ECG, PPG and acceleration. The other is sensor-embedded type with motion monitoring function, which also can measure the data and uses the built-in cellular phone network modem for remote connection. These devices are expected to be useful for ubiquitous healthcare in coming aged society in Korea.

• Korean Institute of Interior Design Journal
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• v.26 no.6
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• pp.62-70
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• 2017

This study has a purpose that definitize correlationship of spatial structure and sales strategies in mixed-use complexes which established in Korea since year 2000. For this purpose, this study tries to analysis spatial structure of mixed-use facilities through space syntax theory and makes an typological categorization based on their space composition. As a result of categorization, Korean mixed-use facilities can be classed as three types. First type is integrated stacking type. Second one is parallel connecting type. Third type is room to room type. According to differences between categories, their spatial structures show different meaning with different sales strategies. Integrated stacking type sales luxury brands and expensive stuffs and it also has deep and complicated structure. That means theses spaces usually make a strategy of exclusion. Parallel connecting type sales special categories and it also has shallow and easy spatial structure. That means these facilities want to make a smooth connection between apposed volumes. Room to room type sales cheap and fancy objects and it also has simple and shallow structure. That means simple spatial structure can be lead contact customer to stuffs. These results mean spatial structure have a effect on design of sales space.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.66-71
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• 2018

In general, when an existing pier is enlarged and reinforced using a small diameter pile, bonded anchor with deformed reinforcing bars is used to maintain the integrity of the joint. However, in the case of bonded anchors, the performance depends largely on the type of joint material. Nevertheless, unlike mechanical anchors, there is no standard method for designing appropriate design methods and proper performance evaluation. Therefore, in this study, the performance of the anchoring anchor was evaluated by performing a model experiment using the reinforcing bars and anchor reinforcing bars. Experimental results show that the structural performance of the unbonded specimen is the best, and the failure mode is the punching shear failure. The deflection of the end of the member is smaller than that of the unconnected member, The deflection of the connected member is larger than the deflection of the small connected member. As the load increases, the possibility of slippage of the anchor steel or fold connection rebar is high.

• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.233-242
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• 2013

This paper reports a new beam-to-column connection that is suitable for use in the weak axis of a column. The proposed system mainly uses bolts, and it minimizes the use of welding, which is generally difficult to perform onsite. In this system, a H-shape steel beam is joined to a H-shape steel column by bolted splices at the top flange and without a scallop at the web. The structural performance of the proposed connection was verified through full-scale tests of nine specimens, taking into account the effects of the geometry and arrangement of the plate.

• Journal of Advanced Navigation Technology
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• v.6 no.1
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• pp.77-83
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• 2002

The emergence of Bluetooth as a radio interface scheme has allowed electronic devices to be instantly interconnected as ad-hoc networks. These short range ad-hoc wireless networks are called piconets, operated in the unlicensed 2.45 GHz ISM(Industrial, Scientific, Medical) band where up to eight devices may be used to configure single or overlapping piconets. In this paper, we have simulated the PER(Packet Error Rate), the ratio of received packet and payload BER(Bit Error Rate) of piconet with packet types of Bluetooth ACL/SCO(Asynchronous Connection Less/Synchronous Connection Oriented) link over wireless ad-hoc environment. The Rayleigh fading effects are considered as channel model, and the simulation results are based on the baseband model of Bluetooth specification. From the simulation results, the PER and the throughput of Bluetooth piconet are sensibly affected by the packet type of ACL/SCO link.

• Journal of Korean Society of Steel Construction
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• v.30 no.2
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• pp.77-85
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• 2018

A through diaphragm is often used to ensure their stiffness for moment-resisting connections using rectangular steel-tube column and H-shaped beam. The through-diaphragm connections, however, have some difficulties for their applicabilities to the field due to the complexity of the fabrication and construction processes. This study thus proposes a new modular system of steel structures assembled only using bolts without welding, by bringing a connection module composed of rectangular steel-tube column, H-shaped beam and oneway bolt onto the site. An experimental study to evaluate the seismic performance of the proposed connection details based on the new modular system is then conducted. The length and type of the inner reinforcement plate are considered as the primary design parameters, and the strength, stiffness, ductility and energy dissipation capability of the new connections are experimentally analyzed by comparison to those of conventional through diaphragm connections.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.4
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• pp.61-70
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• 1999

Cracking was observed in beam-to-column connections of many steel building frames during the 1994 Northridge and 1995 Kobe earthquakes. Thus extensive experimental researches are currently being conducted to improve the seismic performance of steel frames. A value of 0.015 radian was considered as a reasonable estimate of beam plastic rotation demand in steel moment-resisting frames subjected to severe earthquakes. The objective of this research is to develop a type of connection detail which moves the plastic hinge region in the beam away from the face of the column and can prevent cracking at the welded flange of the beam-to-column connection under seismic loading. An experimental investigation was undertaken on five beam-to-column connection specimens to study the performance of the connections with proposed details. The experiemental results showed that the flexural strength and rotational ductility of the beam connections were adequate for the seismic resistance steel frames to prevent possible cracks at the connections.