• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1283-1288
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• 2015

In general, IC chip circuit which is operating a cryptographic computation tends to radiate stronger electromagnetic signal to the outside. By using a power detecter such as a loop antenna near cryptographic device, the encryption key can be identified by probing a electromagnetic signal. To implement a method against non-invasive type attack, multi dielectric slab structure on IC chip to suppress radiated electromagnetic signal was introduced. Multiple dielectric slab was implemented by suitably configured to have the Bragg reflection characteristics, and then the reflection response was computed and verified its effectiveness. As a result, the thickness of the dielectric coating was 2mm and the reflection response characteristics for the vertical incidence was achieved to be 91% level.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.84-93
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• 2016

The signal characteristic of radar wave on concrete decks is determined by the attenuation of the radar due to the conversion of EM(Electromagnetic) energy to thermal energy through electrical conduction, dielectric relaxation, scattering, and geometric spreading. In this study, it is found that the attenuation of radar signal received on top rebars in bare deck concrete with 2 way travel time shows a general decreasing linear trend because of its same relative permittivity and conductivity. The radar signal after depth-normalization, can then be interpreted as being principally influenced by the content of chlorides penetrating cover concrete, which caused corrosion of rebars in bridge decks.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.1
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• pp.68-76
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• 2007

In the present study, tests for U-type steel box girder are performed to observe the effects of W-type and X-type of top lateral bracings on the bending behavior of the U-type steel box girder system. Another objective of the present study is to investigate the adequacy of the currently available design formula. For the structural tests, the test specimen with two third scale of the system constructed in the field was used. In this test, several different spacings are used for the top lateral bracings. The stresses measured from the bending tests are compared with those by the formula proposed by Helwig. An adequate type and the required number of panel for diagonal bracing was obtained.

• Economic and Environmental Geology
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• v.31 no.3
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• pp.235-247
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• 1998

A new technique of simultaneons inversion for 3-D seismic velocity structure by using direct, reflected, and refracted waves is applied to the center of the Korean Peninsula including Pyongnam Basin, Kyonggi Massif, Okchon Fold Zone, Taebaeksan Fold Zone, Ryongnam Massif and Kyongsang Basin. Pg, Sg, PmP, SmS, Pn, and Sn arrival times of 32 events with 404 seismic rays are inverted for locations and crustal structure. 5 ($1^{\circ}$ along the latitude)${\times}6$ ($0.5^{\circ}$ along the longitude) ${\times}8$ block (4 km each layer) model was inverted. 3-D seismic crustal velocity tomography including eight sections from the surface to the Moho, eight profiles along latitude and longitude and the Moho depth distribution was determined. The results are as follows: (1) the average velocity and thickness of sediment are 5.15 km/sec and 3-4 km, and the velocity of basement is 6.12 km/sec. (2) the velocities fluctuate strongly in the upper crust, and the velocity distribution of the lower crust under Conrad appears basically horizontal. (3) the average depth of Moho is 29.8 km and velocity is 7.97 km/sec. (4) from the sedimentary depth and velocity, basement thickness and velocity, form of the upper crust, the Moho depth and form of the remarkable crustal velocity differences among Pyongnam Basin, Kyonggi Massif, Okchon Zone, Ryongnam Massif and Kyongsang Basin can be found. (5) The different crustal features of ocean and continent crust are obvious. (6) Some deep index of the Chugaryong Rift Zone can be located from the cross section profiles. (7) We note that there are big anisotropy bodies near north of Seoul and Hongsung in the upper crust, implying that they may be related to the Chugaryong Rift Zone and deep fault systems.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.2
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• pp.1-7
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• 2021

The concrete deck slab at the continuous span support of the steel box girder bridge is a structure that is combined with the upper flange. It is a structure that can cause tension cracks in the deck slab at the support causing problems such as durability degradation in long span bridges. This is because the tensile stress in the longitudinal direction of the slab exceeds the design tensile strength due to the effects of dead load and live load when applying a long span. Accordingly, it is necessary to control tensile cracking by adding a reinforcing bar in the axial direction to the slab at the support and to introduce additional compressive stress. To solve this problem, a structural system of a steel box girder bridge was proposed that introduces compressive stress as PS steel wire tension in the tensile stress section of the upper slab in the continuous support. The resulting structural performance was compared and verified through the finite element analysis and the steel wire tension test of the actual specimen. By introducing compressive stress that can control the tensile stress and cracking of the slab generated in the negative moment through the tension of the PS steel wire, it is possible to improve structural safety and strengthen durability compared to the existing steel box girder bridge.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.3
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• pp.227-239
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• 2003

For environment-friendly construction, cut-and-cover tunnels have been constructed, thereby leading to embankment slopes with a number of steps. The slopes cause eccentric load on concrete lining of the tunnel. Nevertheless, uniform vertical and horizontal earth pressures, which are determined by considering a self-weight of embankment and $K_0$, are routinely used in structural calculation. Distribution of the earth pressures applied to the lining will lead to a biased calculation far from the actual behavior of the lining. In this study, basic study, therefore, was performed to consider the eccentric load properly in design and analysis of a cut-and-cover tunnel. A method capable of considering the eccentric load in design was proposed and its applicability was numerically examined through a number of examples.

• Journal of Korean Society of Steel Construction
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• v.15 no.4 s.65
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• pp.403-412
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• 2003

The composite metal deck plate system has been widely used for office structures. Recently, however, the flat deck plate has been developed to apply the composite slab system to residential structures. Reduction in construction cost and time can be expected by using expanded metal instead of wire mesh as crack control reinforcements. This study proposed a composite slab system composed of a new-shaped steel deck plate and expanded metal. Twelve specimens were tested to evaluate the structural performance of the new composite slab system. The test results were summarized mainly in terms of maximum load carrying capacity and failure behaviors of each specimen.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.594-601
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• 2019

A true MSEW abutment is an abutment type that directly supports the load of a superstructure. Metal strips, which are in-extensile reinforcements, should be used to minimize abutment deformation. A study to derive the application conditions of a True MSEW abutment was carried out by Zevogolis(2007). As a result, the pullout factor of safety of the uppermost reinforcement was estimated to be the smallest. Therefore, the pullout factor of safety of the uppermost reinforcement is the most important design factor. Parameter analysis was conducted with the abutment length, abutment heel, and abutment height as variables. The pullout factor of safety increased with increasing abutment length and abutment heel length. This is because the contact area increases and the superstructure is dispersed as the abutment length and abutment heel length increase. The pullout factor of safety converges at an abutment length of 1.2m and an abutment heel length of 0.9m. This is because the effective length of the reinforcement is reduced due to the increase in contact area. On the other hand, the extension of the superstructure will increase if the abutment length and abutment heel length are increased excessively. In addition, earth-volume is increased if the abutment height increases excessively. This acts as an upper load on the MSE wall. Therefore, it needs to be examined carefully.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.37-39
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• 2006

본 연구에서는 상변화소자의 구조 변화에 따른 열전달 현상과 reset 전류에 대한 시뮬레이션을 실행하였다. 상변화소자의 상변화재료의 profile에 따른 주울열의 발생 및 reset 전류의 변화량을 시뮬레이션 한 결과, 하부전극에서부터 도포되는 상변화재료 박막의 두께가 2000[A]인 경우는 541($^{\circ}C$)로 현저하게 발열온도가 낮아지는 것을 알 수 있다. 이는 저항체로 쓰이는 상변화재료의 저항 감소로 인해 발열량이 적게 되고 상변화재료를 통해 전달된 열이 상부전극 텅스텐과 접촉하면서 외부로 쉽게 전달되면서 빠져나감에 따라 온도가 많이 올라가지 않는 것으로 생각된다.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.315-319
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• 2007

지하에 설 치된 맨홀의 구조물이 노후되거나, 내부에 수 용된 시설물로 작업 공간이 협소하여 맨홀 구조물을 대개체 할 펼요가 있을 경우, 지금까지는 대부분 현장 콘크리트 타설에 의한 방법을 사용하였다. 이러한 방법은 거푸집 시공, 콘크리트 타설, 콘크리트 양생, 거푸집 철거 등의 공정이 소요되어 공사 기간이 장기화 되고, 도심지에 위치한 맨홀인 경우에는 차량과 보행자의 통행 불편을 초래하기도 하였다. 또한, 통상적으로 사용되고 있는 프리캐스트 맨홀에 비해 시공 품질이 낮아 향후 맨홀의 운용 및 유지관리에 많은 어려움을 겪는 원인이 되기도 하였다. 본 논문에서는 이러한 문제점들을 해결하기 위해, 폴리머 콘크리트를 이용하여 하부, 벽체, 상부로 구성된 다수의 세그먼트를 생산한 후, 현장에서 이들 세그먼트를 조립하여 맨홀을 설치하는 방법을 연구하였다. 가변형 거푸집을 이용한 세그먼트 제작과 조립식 블록에 의한 관구를 사용하여 현장 적용성을 높임은 물론, 프리캐스트로 생산되는 폴리머 콘크리트 맨홀 수준의 시공 품질을 확보할 수 있도록 하였다.