• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.863-867
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• 2007

In this paper, We have designed miniature microstrip patch antenna based on fractal structure using L-shaped feeding structure for 4G mobile communication applications. Miniature antenna has achieved by the presence of unusual fundamental resonant mode which we call "crossed-diagonal"(CD)current. Using CST Microwave Studio 5.0, patch antenna was designed. The simulated input return loss showed the bandwidth of 1.2647[GHz]($2.944{\sim}4.209GHz$), 35.4% below -10dB. The gain of E, H-plane was achieved 8.3dBi and 8.4dBi respectively. And beamwidth of 3dB in the E, H-plane was $40.6^{\circ}$ and $81.6^{\circ}$, respectively.

• Journal of Internet of Things and Convergence
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• v.9 no.3
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• pp.21-26
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• 2023

The development and distribution approach of applications is transitioning from a monolithic architecture to microservices and containerization, a lightweight virtualization technology, is becoming a core IT technology. However, unlike traditional virtual machines based on hypervisors, container technology does not provide concrete security boundaries as it shares the same kernel. According to various preceding studies, there are many security vulnerabilities in most container images that are currently shared. Accordingly, attackers may attempt exploitation by using security vulnerabilities, which may seriously affect the system environment. Therefore, in this study, we propose an efficient automated deployment pipeline design to prevent the distribution of container images with security vulnerabilities, aiming to provide a secure container environment. Through this approach, we can ensure a safe container environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1177-1183
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• 2010

In this paper, design of a microstrip-fed, Spidron fractal-shaped slot antenna with circular polarization is represented. The ground plane of the designed antenna has a slot that comprises seven right-angled triangle next to each other in a low. A reflector is placed at the bottom on microstrip feeding line to enhance the antenna gain. The optimized design was conducted by varying a length of the first right-angled triangle, location of feeding line, space between a substrate and a reflector. The proposed antenna was fabricated on a Taconic-RF35 substrate. The entire dimension of the fabricated antenna is $40{\times}40{\times}18.6mm^3$ and the reflector is 18.6 mm away from the ground plane. The measured gain of the fabricated antenna is 6.7 dBi at 4.3 GHz. The measured bandwidths of -10 dB reflection and 3 dB axial ratio are 41 % and 7.4 %, respectively.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.147-155
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• 2005

In this paper, we propose that three uniform coplanar waveguides(CPWs), such as a conventional, finite grounded(FG), and grounded(G) CPWs, can be coupled with a $TE_{01{\delta}}$ mode dielectric resonator(DR) for a parallel resonant characteristic as a microstrip line coupled with the DR. Coupling characteristics have been investigated by placing the DR on a dielectric support above the CPWs and by moving the DR away from the center of a slot of the CPWs to the ground plane. FEM simulation(HFSS) results in terms of S-parameters agree well with measurement results. Finally, unloaded Q values of the DR coupled with the three uniform CPWs are compared with those of the DR coupled with a microstrip line. The comparison shows that the DR coupled with the three CPWs has higher unloaded Qs than that coupled with a microstrip line and that the GCPW case has the highest unloaded Qs.

• Journal of The Korean Association of Information Education
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• v.22 no.2
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• pp.231-238
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• 2018

Software education has started as a compulsary subject or part in elementary, middle and high school, but there is a limitation for using the physical computing toolkit and instructional guidelines that teacher can use. The purpose of this study is to propose a computing education program using a physical computing toolkit called the Micro:bit. The novel instructional model is called "MDIAP" which consists of five stages : Motivation, Demonstration, Imitation, Application, Presentation. Instructional process is presented in spiral, consisting of basic micro-bit sensors, and maker's learning using additional sensors and actuators. This study will help students to enhance creative computational thinking through the MDIAP instructional activities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.308-314
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• 2006

A line scan camera is applied to enhance COG(Chip On Glass) inspection accuracy to be measured a few micro unit. The foreign substance detection among various faulty factors has been the most difficult technology in the faulty automatic inspection step since COG pattern is very miniature and complexity. In this paper, we proposed two step area segmentation template matching method to increase matching speed. Futhermore to detect foreign substance(such as dust, scratch) with a few micro unit, the new method using gradient mask and AND operation was proposed. The proposed 2 step template matching method increased 0.3 - 0.4 second matching speed compared with conventional correlation coefficient. Also, the proposed foreign substance applied masks enhanced $5-8\%$ faulty detection rate compared with conventional no mask application method.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06b
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• pp.261-266
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• 2007

내장형 시스템에 보다 강력한 성능이 요구됨에 따라 내장형 마이크로 프로세서는 보다 깊은 파이프라인을 채택하고 있다. 따라서, 내장형 마이크로 프로세서는 보다 정확한 분기 예측기를 필요로 하고 있다. 이러한 상황에서 분기 예특기의 구조, 성능 및 전력 소모와 전체 시스템의 전력 소모 사이의 trade-off를 분석하는 것은 매우 중요하다. 내장형 환경에서 시스템의 전력 소모는 설계 시 매우 중요하게 고려되어야 한다. 특히 내장형 시스템의 요구사항은 동작할 응용 프로그램에 의하여 규정되고, 전력 소모도 응용프로그램의 구조와 강하게 연관되어 있다. 본 논문의 목표는 내장형 환경에서 성능-전력 공간에서 분기 예측기를 분석하는 기법을 제시하는 것에 있다. 이를 통하여, 분기 예측기 테이블의 성능-전력을 고려한 최적화된 크기를 찾을 수 있다. 이러한 목표는 수학적 모델링을 통한 정량적 예측의 수행 및 시뮬레이션 결과와의 비교를 통한 수학적 모델링의 검증의 과정을 통하여 이루어진다. 결과는 우리의 수학적 모델이 성능-전력 공간에서 분기 예측기 테이블의 최적화된 크기 결정의 해법을 제공하고 있음을 보여주고 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1963-1970
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• 1998

In this paper, a two-dimensional slotline coupling structure is proposed for the planar active phased array antenna system with scanning the beam by coupled oscillators without phase shifters. The operating characteristics are analyzed and experimentally demonstrated. The proposed two-dimensional slotline coupling structure consists of $|{=}|$-type slotline in the ground plane for the coupling of E-plane and H-plane. From the simulation results of coupling strength with the variation of width, length and the number of slotlines, the optimal coupling structure is proposed and applied to $2{\times}5$ elements of planear phased array antenna. The experimental results show that the beamwidth of E-plane and H-pland are $42^{\circ}$ and $15^{\circ}$, respectivly, and the scanning range is from $-20^{\circ}$ to $15^{\circ}$ from the broadside. Therefore, it is shown the two-dimensional slotline coupling structure for oscillator-type active phased array antenna can be applied to the planar phased array antenna system.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.263-271
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• 2016

This study investigated the hydraulic impact scope and dissolved oxygen (DO) concentration distribution by the micro-bubble aeration in the Juksan Lake located in Asan city in Chungcheongnam-do province. A tracing experiment for hydraulic impact scope was used which constituted a 20% rhodamine solution. A 160 m-guideline was installed in the horizontal direction of the micro-bubble jet flow and the rhodamine concentration, water temperature, and DO concentration were measured at depths of 1 m, 2 m, and 3 m at intervals of 10 m. In the Juksan Lake, the effective range of jet flow discharged by the micro-bubble generator was about 40 m, and after then the jet plume moved up to 80 m to 120 m through the advection and diffusion processes of ambient water. DO concentration in the lake was maintained at 7.4-12.6 mg/L during tracking experiment. The DO of the lake sediments improved from 0.2 mg/L to 8.0 mg/L after applying micro-bubble aeration. In conclusion, the micro-bubble aeration can be an effective technology for the management and improvement of water quality in an agricultural reservoir.

• Smart Media Journal
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• v.12 no.9
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• pp.60-71
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• 2023

A microservice architecture that accommodates the heterogeneity of various development environments and enables flexible maintenance can secure business agility to manage services in line with rapidly changing requirements. Due to the nature of MSA, where communication between microservices within a service is frequent, the boundary security that has been used in the past is not sufficient in terms of security, and a Zerotrust system is required. In addition, as the size of microservices increases, definition of access control policies according to the API format of each service is required, and difficulties in policy management increase, such as unnecessary governance overhead in the process of redistributing services. In this paper, we propose a microservice architecture that centrally manages policies by separating access control decision and enforcement with a general-purpose policy engine called OPA (Open Policy Agent) for collective and flexible policy management in Zerotrust security-applied environments.