• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1864-1865
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• 2006

무인지능형로봇 시스템에 있어서 자세의 정확도를 향상시키기 위한 많은 연구가 이루어져 왔다. 시스템의 자세 제어는 사용되는 모터의 위치 제어로 대응된다. 이와 같은 시스템은 운용 시에 충격 진동이 발생하게 된다. 이러한 충격 진동 외란을 잘 제거해야 요구되는 위치 정도로 제어를 수행할 수 있다. 로봇 제어 분야에서 불확실한 로봇에 대한 자세 제어 분야는 가장 기본적이면서 중요한 분야중의 하나이다. 이러한 문제를 다루기 위하여 계산 토크 방식에 기초한 선형 제어 기법이나 적응 제어 기법, 강인 제어 기법 등을 이용한 연구 결과들이 발표되고 있다. 그러나 그러한 기법은 일반적으로 로봇의 정확한 동력학식을 알아야 하며, 구현하기 복잡하다. 따라서 본 논문에서는 적응 규칙에 의하여 모델의 불확실성, 시스템의 변화, 외란으로 인해 발생하는 공칭 플랜트와의 오차를 보상하도록 제어 입력을 생성하는 내부 루프 부분과 공칭 플랜트 모델의 명령을 추종하도록 하는 제어 입력을 생성하는 외부 루프 부분으로 구성되는 방법인 외란관측기(Disturbance OBserver : DOB) 제어 알고리즘을 제안한다. 또한 프로세서의 신뢰성과 수치 연산 및 알고리즘의 빠른 처리를 위해 현재 사용 빈도가 높은 TI사의 DSP시리즈 중에서 부동 소수점 연산 기능을 가지면서 모터 제어에 적합한 TMS320C2000계열의 TMS320F2812을 사용하여, 운용 시 발생되는 진동 둥에 대한 외란 제거를 목적으로 한다. 본 논문은 규명된 시스템 모델식을 바탕으로 DOB 제어 시뮬레이션을 수행하고 PMSM 모터모델 시뮬링크 블록을 구성하여 검증된 외란 관측기 제어 알고리즘을 검증한다. 시뮬레이션으로 검증된 DOB 모터 자세 제어 알고리즘을 DSP에 적용하기 위해 코드변환하고 모터 실험 시스템에 실제 적용함으로써 타당성을 검증하여 상용 제어기로 실제 현장에 적용 가능함을 입증한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.21-32
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• 1999

Mapping and precise point determination by photogrammetry have been shown to be an economic solution. But control points are necessary to determine the exterior orientation parameters. Although the number of required control points has been reduced based on extended bundle adjustment and reinforced cross-strip, the ground survey is a significant factor of whole expenses in photogrammetry. The status of GPS-photogrammetry with kinematic DGPS-positioning to overcome this disadvantages, is now steadly progressive since the first possibility has been proved. The completed satellite configuration, powerful receiver function and upgraded software for kinematic DGPS-positioning have extensively improved the accuracy of combined bundle adjustment. So the research for the operational use of GPS-photogrammetry is absolutely necessary. The presented test field was designed for identification of subsidences in a coal mining area, flown with 60％ sidelap and cross strips. Just with 6 control points and combined block adjustment instead of the traditionally used 21 horizontal and 81 vertical control points the same ground accuracy has been reached. The accuracy of kinematic GPS-positioning and combined block adjustment was independent upon the distance of the ground reference station. It also has been showed that the special model for the systematic error correction in the combined block adjustment.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.91-98
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• 2009

This paper presents a solution to error avalanche of deciphering where radio noise brings random bit errors in encrypted image data under ubiquitous environment. The image capturing module is to be made comprising data compression and encryption features to reduce data traffic volume and to protect privacy. Block cipher algorithms may experience error avalanche: multiple pixel defects due to single bit error in an encrypted message. The new fault tolerant scheme addresses error avalanche effect exploiting a three-dimensional data shuffling process, which disperses error bits on many frames resulting in sparsely isolated errors. Averaging or majority voting with neighboring pixels can tolerate prominent pixel defects without increase in data volume due to error correction. This scheme has 33% lower data traffic load with respect to the conventional Hamming code based approach.

• Journal of Broadcast Engineering
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• v.4 no.1
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• pp.12-21
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• 1999

Without a question. the most significant new medium for transmitting information is the Internet. Unfortunately. the multimedia elements that enrich our titles are extremely bulky. While the Internet hype is available in unlimited supply. Internet bandwidth and functionality of web browser are not making the net quite hospitable to multimedia data formats. In this thesis. for smoother and better communications over the net. a study is done on still image compression techniques. based on wavelet transform which is selected on MPEG-4 as a still image compression standard and a strong candidate for the JPEG-2000 standard. For Internet service. the study of plug-in programming and ActiveX control is implemented to enrich the functionality of web browser. As a result. the proposed still image service gives better image quality than current standard JPEG and does not yield to the common blocking artifacts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2233-2248
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• 1999

The TMN that appears to operate the various communication networks generally and efficiently is developed under the different platform environment such as the different hardware and the different operating system. One of the main problems is that all the agents of the TMN system must be duplicated and maintain the software and the data blocks that perform the identical function. Therefore, the standard of the Q3 interface development cannot be defined and the multi-platform cannot be supported in the development of the TMN agent. In order to overcome these problems, the Farming methodology that is based on the Farmer model has been suggested. With the Farming methodology, the software and the data components which are duplicated and stored in each distributed object are saved in the platform independent class repository(PICR) by converting into the format of the independent componentware in the platform, so that the componentwares that are essential for the execution can be loaded and used statically or dynamically from PICR as described in the framework of each distributed object. The distributed TMN agent of the personal communication network is designed and developed by using the Farmer model.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.154-161
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• 2009

Recently, as many functional blocks are integrated on a small area the high speed integrated circuits emerge as a critical electromagnetic interferer which causes mal-function of adjacent circuitries and lowers the sensitivity of the wireless receivers. Therefore, it is necessary to devise an precise analyzing tool to pinpoint the major electromagnetic noise contributor among the internal circuit blocks of high speed IC's. This paper presents the design, fabrication, and measurement results of the high resolution magnetic field probe which can measure the current density on the IC surface. In order to achieve the high resolution, the magnetic field probe is fabricated using 3-metal semiconductor process so that its thickness is reduced by 10% than that of conventional works. Through the magnetostatic analysis and EM simulation, spatial resolution and sensitivity to the nonmagnetic field components are analyzed. Experimentally, it is found that the fabricated probe can measure the current density on the IC surface with $210{\mu}m$-spatial-resolution.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.64-71
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• 2009

This paper presents an efficient frame synchronizer architecture using the common autocorrelator for Digital Video Broadcasting via Satellite, Second generation(DVB-S2). To achieve the satisfactory performance under severe channel conditions and the efficient hardware resource utilization of functional synchronization blocks which have been implemented, we propose a new efficient common autocorrelator structure. The proposed architecture can improve the performance of the frame and frequency synchronizer since each block operates jointly in parallel and significantly reduce the complexity of the frame synchronizer. Hence, The proposed architecture can ensure the decrease by about 92% multipliers and 81% adders compared with the direct implementation. Moreover, it has been thoroughly verified with an FPGA board and R&STM SFU broadcast test equipment and consists of 29,821 LUTs with XilinxTM Virtex IV LX200.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.90-97
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• 2006

In this paper, we present a cost-effective architecture of high-speed soft-decision Viterbi decoder for Multi-band OFDM(MB-OFDM) systems. In the design of modem for MB-OFDM systems, a parallel processing architecture is general]y used for the reliable hardware implementation, because the systems should support a very high-speed data rate of at most 480Mbps. A Viterbi decoder also should be designed by using a parallel processing structure and support a very high-speed data rate. Therefore, we present a optimized hardware architecture for 4-way parallel processing Viterbi decoder in this paper. In order to optimize the hardware of Viterbi decoder, we compare and analyze various ACS architectures and find the optimal one among them with respect to hardware complexity and operating frequency The Viterbi decoder with a optimal hardware architecture is designed and verified by using Verilog HDL, and synthesized into gate-level circuits with TSMC 0.13um library. In the synthesis results, we find that the Viterbi decoder contains about 280K gates and works properly at the speed required in MB-OFDM systems.

• The Journal of the Korea Contents Association
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• v.15 no.10
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• pp.561-569
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• 2015

Many start-ups have many realistic hardships in getting management diagnosis about whether their business model are properly going. For this reason, there is the need for an easy and simple method that makes it possible to conduct a strategic management through the analysis and management diagnosis of the business model. The Business Model Canvas(BMC) has been popularized as a tool to help entrepreneurs describe, design, challenge, invent and pivot their business model. This model gives a framework to describe the most important building blocks(9 blocks) of existing business. Entrepreneurs can make their own business analyses and craft their own solutions through using this model. In this study, we conducted consulting by using the BMC on the NARUATO which is a small start-up in the healthy food industry. This case study can use as a learning material for entrepreneurship education.

• The Journal of Society for e-Business Studies
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• v.25 no.2
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• pp.109-126
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• 2020

This study attempts to find out the characteristics of digital currency and currency transformation through the analytical descriptions of the literature. In the early days of the emergence of new currency, market-oriented autonomous monetary adjustment was made along with various attempts by the private sector, and then government-centered central currency management and coordination were made for the national monopoly of profits and power. Digital currency can be seen as the emergence of a new form of money that will bring about paradigm changes. CBDC can be divided into direct and indirect types. CBDC is expected to require a strategic approach by the government or firm as it will bring about changes in the ecosystem of related industries. Libra is a stablecoin designed to minimize price fluctuations, and if it succeeds in commercializing it, it is expected to bring about revolutionary changes in the financial industry around the world.