• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.245-252
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• 2018

In this paper, the dual band circular polarization patch antenna was designed by using band rejection characteristics of CSRR structure for geostationary satellites. A quadrangular CSRR structure was etched on the ground at the rear of the patch antenna's feed to obtain band rejection characteristics in between the receiving frequency band(1525~1559MHz) and transmission band(1626.5~1660.5MHz), and the corner of the patch antenna was truncated to enable circular polarization. It was confirmed that the resonant frequency of the patch antenna differs according to the size anc location of the CSRR and cirular polarization characteristics with simulation and measurement results. Measurement results shows the gain of about 0.2dB and 1.5dB in the TX and RX band.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.69-75
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• 2001

Photoimageable thick film technology is a new technology in that the lithography process such as exposure and development is applied to the conventional thick film process. Line resolution of 25 $\mu\textrm{m}$ width and 25 $\mu\textrm{m}$ space could be obtained by laminating green sheet, printing photoimageable Ag paste, exposing the test patterns, developing, and co-firing. In case of using the alumina substrate, 20 $\mu\textrm{m}$ fine line could be also obtained by similar process. Test results showed that exposing power density and developing time were the most important processing parameters for the fine line formation. Microstrip and series gap resonators with well-defined line morphology and good transmission characteristics in high frequency were formed by this new technology, and thereby dielectric constant and loss of test substrate were calculated.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.159-163
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• 2002

So far, many kinds of researches on the chip components and MCM-C RF module especially on the 3-dimensional ceramic module using embedded passives have been performed. LTCC system has many kinds of advantages, like low loss, low cost of process, stability of process etc..The electrical behaviors of components are affected by that of the material systems including dielectrics and conductors. In this study, many kinds of conductor pastes in the variation with metal content and grain size are fabricated and their effect on the characteristics of stripline resonator are examined upto 6 ㎓.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.6
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• pp.51-58
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• 2022

Microcontroller (MCU) is designed to properly utilize each module through programming by connecting various modules to Advanced Microcontroller Bus Architecture (AMBA). General-purpose MCUs are designed for consumers to use them appropriately in their research or industry area. However, in a specific area such as networking and AI autonomous vehicles, it is necessary to design MCU suitable for the field directly. However, there is a significant barrier for most consumers to directly design an MCU. In this paper, we provide a development guideline that can easily design an MCU for education or research purpose. First, we introduce AMBA system with open IPs, and we verify that the module operates properly through AMBA and interrupt operation. Finally, the MCU system is designed as an on-chip.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.197-203
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• 2002

This paper proposes a new agent based mechanism called a Multicast Handoff Agent (MHA) to reduce handoff latency for IP multicast. The MHA acts as a proxy for an Internet Group Management Protocol (IGMP) of Mobile Nodes (MNs) at each Base Station (BS) and keeps information for members of multicast groups in a cell. When an MN moves to a next cell, the MHA immediately sends unsolicited reports without waiting for the IGMP query. The mechanism was evaluated through simulation and analysis and compared with the IGMPv2 for micro-mobility and the IGMP traffic. Simulation results show that handoff latency for micro-mobility can be largely reduced and the IGMP control traffic on the wireless links during the duration of membership can be eliminated. Thus, this mechanism is superior to the existing mechanism in both micro-mobility and battery duration, as the need not to reply to a query conserves battery power.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.185-190
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• 2015

In this paper we characterized and designed the waveguide antipodal finline transition at 57-65GHz frequency band in V-band for 5G mobile communication systems. Especially, we proposed the design method of spline taper for finline tapers by means of increasing curvature from linear taper. We could perform optimization more effectively by excluding improper regions for optimal performance from optimization using the method. Return losses and insertion losses of antipodal finline transitions were mainly affected by the taper shape of the finline. The resonances in the structure of the finline transition were the strongest enemies who deteriorate the performance of the transition. And we alleviated the resonances using semicircle shaped patch. The designed antipodal finline transition showed good performance as it showed less than -24.2dB of return loss and -0.24dB of insertion loss in the band(57-65GHz) which we suppose to use.

• Journal of Internet Computing and Services
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• v.6 no.4
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• pp.21-35
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• 2005

Software product-lines is the software development paradigm to attain the rapid development of quality applications by customizing the reconfigurable components and composing them based on predefined software architectures. Recently various methodologies for the component-based product lines are proposed, but these don't provide the specific implementation techniques of the components in terms of variability resolution mechanism. In other hand, the several approaches to implement the component supporting the variabilities resolution are developed, but these don't define the systematic analysis and design method considering the variabilities from the initial phase. This paper proposes the integration of PLUS, the one of product line methodologies extending UML modeling, and component code generation technique in order to increase the efficiency of producing the specific product in the software product lines. In this paper, the component has the hierarchical architecture consisting of the implementation elements, and each implementation elements are implemented as XSLT scripts. The codes of the components are generated from the feature selection. Using the microwave oven product lines as case study, the development process for the reconfigurable components supporting the automatic variability resolution is described.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.11
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• pp.45-52
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• 1994

In recent days low cost, high performance microprocessors have led to construction of medium scale shared memory multiprocessor systems with shared bus. Such multiprocessor systems are heavily influenced by the structures of memory systems and memory systems become more important factor in design space as microprocessors are getting faster. Even though local cache memories are very common for such systems, the latency on access to the shared memory limits throughput and scalability. There have been many researches on the memory structure for multiprocessor systems. In this paper, an asynchronous memory architecture is proposed to utilize the bandwith of system bus effectively as well as to provide flexibility of implementation. The effect of the proposed architecture if shown by simulation. We choose, as our model of the shared bus is HiPi+Bus which is designed by ETRI to meet the requirements of the High-Speed Midrange Computer System. The simulation is done by using Verilog hardware decription language. With this simulation, it is explored that the proposed asynchronous memory architecture keeps the utilization of system bus low enough to provide better throughput and scalibility. The implementation trade-offs are also described in this paper. The asynchronous memory is implemented and tested under the prototype testing environment by using test program. This intensive test has validated the operation of the proposed architecture.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.195-206
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• 2023

Most of the Micro-mobility parking in Korea use Dockless system. However, Dockless can result in cluttering, infrastructure deficiencies, and safety challenges as has been observed in cities. It is necessary to introduce a Station Parking system in order to solve the drawbacks of the dockless, but the introduction without engineering has low accessibility and induces side effects. In this study, to decide optimal location about number of the Micro-mobility Station, we has been applied the MCLP model about the coverage range, usage demand, usage time in order to classify the type of Micro-mobility Station. For the MCLP, User Date input to reflect realistic demand in Bundang new town, Korea. The result show that the optimal number of facilities in 400 m was 146, and the coverage ratio was 99.83 %, which was most suitable coverage for solving the parking problem. We also classified the demand into 4 levels and the usage time into 3 levels, and by crossing them, we were able to classify the Parking lot types into 12 types. It is possible to propose strategic policies in the installation and operation of Micro-mobility Parking System.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1292-1296
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• 2002

In this paper, a 3-coupled microstrip line tunable bandpass filter has been designed on the basis of a tonductoriFerroelectricfDielectric (CFD) structure. This tunable filter basically exploits the fact that the increase in the bias voltage leads to the reduction of the effective dielectric constant (eon). This reduced $\varepsilon$eff shifts the center frequency (fc) to the higher value. The characteristics of designed filter are as follows; Return loss (RL) is larger than 10 dB; Insertion loss (IL) is les.i than 3.5 dB: 3-dB bandwidth (BW) is less than 1.18 GHz fc can be tuned from 25.4 GHz to 28.8 GHz over the variation of $\varepsilon$eff, from 10 to 13. Therefore, the tunability comes up to 3.4 GHz. The dimension of the filter designed is 7.0 mm ${\times}$ 5.0 nm ${\times}$ 0.5 mm.