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Environmental Map Building for a Mobile Robot Using Infrared Range-finder Sensors
Full text linkThe use of infrared range-finder sensors in the environmental recognition system for mobile robot has the advantage of low sensing cost compared with the use of other vision sensors, such as laser range-finder and CCD camera. This paper presents a methodology building the high accuracy environmental map using a mobile robot with low cost infrared range-finder sensors. In the map building using an infrared range-finder sensor, the errors due to non-linearity, specular reflection are contained. In this paper, therefore, the error due to non-linearity is compensated using a neural network. The neural network used consists of multi-layer perceptron and Levenberg-Marquardt algorithm is applied to learn it. And also, the random error of readings and the uncertainty of environment are taken into sensor modeling at probabilistic approach. The map is represented by occupancy grid framework and updated by the Bayesian estimation mechanism. The effectiveness of the proposed method is verified through experiments.목차
Abstract = iii
제1장 서론 = 1
제2장 환경지도 작성용 적외선 레인지파인더 센서 = 5
2.1 환경지도 작성용 센서 = 5
2.2 PB9-01 적외선 레인지파인더 = 8
2.3 센서의 특성분석실험 = 10
2.3.1 실험환경 및 방법 = 11
2.3.2 실험 및 분석결과 = 12
제3장 신경회로망을 이용한 비선형 바이어스오차 보정 = 19
3.1 신경회로망의 개요 = 19
3.1.1 다층 퍼셉트론 = 19
3.1.2 Levenberg-Marquardt 알고리즘 = 20
3.2 비선형 바이어스오차 보정 = 22
3.2.1 신경회로망의 구조 = 22
3.2.2 신경회로망의 학습 = 23
3.2.3 검증실험 = 26
제4장 이동로봇용 환경지도 작성 = 28
4.1 점유격자지도(Occupancy grids map) = 29
4.2 확률적 접근 = 30
4.2.1 베이지안 추론 = 30
4.2.2 우도(Likelihood) 및 우도율(Likelihood ratio) = 31
4.2.3 데이터 융합(Data fusion) = 32
4.3 센서 모델링 = 33
4.4 지역지도의 생성 = 37
4.5 전역지도의 갱신 = 38
제5장 실험 및 고찰 = 40
5.1 대상 로봇시스템 = 41
5.1.1 주모듈 = 42
5.1.2 보조모듈 = 43
5.1.3 소프트웨어 = 44
5.2 실험환경 = 46
5.3 결과 및 검토 = 47
제6장 결론 = 50
참고문헌 = 5
A Study on Target Tracking System for an Intelligent Wheelchair Using Infrared Range-finder and CCd Camera
Full text linkIn this thesis, the target tracking system for an intelligent wheelchair using infrared range-finder and CCD camera is discussed. The tracking system is designed such that the wheelchair can follow a path of human once in a while. The problem of human tracking requires a recognition of feature as well as a tracking of human position. Therefore, infrared range-finder and CCD camera create target candidate through each target recognition algorithm. But, target tracking that uses single vision sensor has low accuracy due to uncertainties of target decision and position error. In this thesis, therefore, a data fusion algorithm which reduces the uncertainties of target decision and corrects the position error of human is proposed. The effectiveness of the proposed method is verified through experiments.목차
Abstract = iii
제1장 서론 = 1
제2장 지능 휠체어 = 4
2.1 전체 시스템의 구성 = 4
2.2 주행 알고리즘 = 7
2.2.1 PWS 기구학 = 7
2.2.2 추측항법에 의한 위치추정 = 8
제3장 표적 추적 시스템 = 10
3.1 시스템의 구성 = 10
3.1.1 적외선 레인지파인더 센서 = 11
3.1.2 CCD 카메라 = 13
3.2 표적 추적 알고리즘 = 15
3.2.1 적외선 레인지파인더를 이용한 표적의 인식 = 15
3.2.2 CCD 카메라를 이용한 표적의 인식 = 21
3.2.3 센서 데이터 융합을 이용한 추적 = 28
제4장 실험 및 고찰 = 33
4.1 실험 환경 = 33
4.2 실험 결과 = 34
제5장 결론 = 40
참고문헌 = 4
A Study on the Power Control System for Electric Machineries using Power Line Communication
Full text linkRecently, a lot of studies on the power line communication(PLC) are being done by many companies and institutes due to its own merit which can use the power line spread widely as a communication channel. But, there are many serious problems about the harsh and unpredictable characteristics, or noise, signal distortion and attenuation so it's difficult to make network with PLC. In this paper, the power line characteristics as the view point of communication channel are investigated and the technologies of PLC are proposed to control the power switch of electric machineries by using the combined method of ASK modulation , transmission, receiving pulse transformer control module and microprocessor technologies. Also experiments are carried out to ascertain performance in case of applying to electric lights control according to various distances as an example.목차
제 1 장 서론 = 5
제 2 장 전력선 반송채널의 특성 = 7
2.1 전력선의 잡음 = 7
2.2 선로 임피던스 = 10
제 3 장 전력선 통신 시스템의 설계 = 13
3.1 공진 콘덴서의 설계 = 13
3.2 송·수신 펄스 트랜스 모듈의 설계 = 15
제 4 장 전력선 통신 시스템의 구현 = 18
4.1 전체 시스템의 구성 = 18
4.2 시스템 프로토콜, 소프트웨어 구조 = 21
4.3 각 유닛의 하드웨어구조 = 25
제 5 장 실험 및 고찰 = 27
제 6 장 결론 = 3
A Study on the Determinant and the Stabilization Scheme of Liner Freight Rates
Full text linkThe global liner shipping industry has been significantly and rapidly changing to meet customer's requirements and shipowner's management styles especially in containerized liner service. Since the advent of container ships in the 1960s, the liner market has been stabilized relatively in supply and demand of ship's slots and freight incomes till the early of 1980s owing to the limited supply of ship's slots and the increase of container cargoes and strong activities of freight conferences as well as self-investigation policies in the main trade lane of Asia/Transpacific and Europe.
However since the late of 1980s, a movement to respect market's principal has spreaded across international trade and liner shipping industriy along with deregulation of various regulatory principles through the strong influences of so called Thatcherism and Reaganomics.
Accordingly in the liner shipping market there were the great changes at the shipper's convenience and interests due to regulatory reforms or revisions in the shipping sector such as Anti-trust rules of the EU in 1987, the Shipping Act of 1984 and the Ocean Shipping Reform Act(OSRA) of 1998 in the United States. With the introduction of these regulations, existing shipping conferences and member carriers had no longer efficiently exercised their market power. Meanwhile, in the liner shipping markets, the negotiating power of shippers against carriers has become stronger it has changed from supplier's oriented market to customer's oriented market.
Moreover, in addition to the above regulatory reforms, the liner carriers have invested a lot of funds to build more and larger vessels in order for them to bring about low costs via economies of scale and to improve profitability. Furthermore the production time needed to build new ships has been reduced drastically to 1-2 years by continuing technological innovation. As a result of this, most liner trade routes have been oversupplied with container vessels since the 1980s. The Korea Maritime Institute(KMI) estimated that surplus ratio of ship's slots will be around 24.5 percent in the worldwide market and an excess capacity of 30 to 40 percent in the Transpacific Trade and Europe-Asia Trade in 2002.
As the consequence of the aforementioned, this inevitably triggered a fierce competition among the liner carriers and thus today's liner shipping market is characterized by chronic overtonnage and lower freight rates. Such structural changes make it difficult for all liner operators to carry out liner business and ultimately it might bring about more difficulties in international freight traffic by disorder and demoralization in the freight market.
In this regard, the purpose of this study attempts to analyze the determinant of liner freight rates and to seek for an effective policy and counter measures to stabilize liner freight market and rates.
In respect to liner freight rates, an empirical and theoretical study was conducted and further extended its analysis by the data collected from a survey questionnaire of local ship operators and international freight forwarders in Korea. The items on the questionnaires were analyzed by using the Reliability Test Method and Factor Analysis Method in respect of the determinant of freight rates and the Structural Equation Modeling in decision making on the management of the liner shipping business.
Before the study of stabilization on the liner freight market and rates, the result of research on the current market trends and changing paradigms in the liner industry are as follows:
(1)The cargo movements of container liners have increased steadily approx. 6 to 12 percent every year and KMI(Korea Maritime Institute) has forecasted that the global container movements in 2002 would be 248 million TEU showing a 142% increase on 103 million TEU in 1991.
(2)Whereas, the number of container vessels and the loading capacity have been increased substantially for the purpose of contributing to the increase in worldwide demand for freight and the existence of economies of scale. KMI also reported that the global loading capacity of container fleets in 2002 is estimated at 5.5 million TEU up 150% from 2.2 million TEU in 1999. The size of vessels ordered by global carriers has become bigger and larger to that of post/super panamax model of 6,000-8,000 TEU capacity as a fifth to seventh generation type. This was followed by some carriers designing 9,000 TEU capacity and presently 10,000 TEU container vessels are under technical consideration. As a result of the ratio of excess ship capacity, the liner shipping market has become more and more competitive.
(3)Another paradigm shift in the liner market is the expansion of strategic alliances and M&A among major carriers. Most carries having bigger vessels have sought partnerships to increase utilization by means of space pooling, space swapping, space chartering and sometimes by participating in strategic alliances and M&A viewing that proper cargo reservation to fulfill the space is not an easy task, especially due to restraints of time. Presently 6 major alliances were forged among 17 leading carriers who owned and operated 1,302 vessels with a total capacity of 3,216,936 TEU.
(4)Nowadays another important paradigm shift in the liner market is the expansion of the service coverage to the offshore and inland area to meet customer's requirements and to create additional profits for the carriers through various extended and total logistic services. Now many shipping carriers are providing warehousing, trucking, terminal operation, consolidation, forwarding and logistics consulting among other services, to satisfy customer's needs under the rubric 'onestop service'.
(5)Another change in the liner shipping industry is the enhancement of transport services made possible by developments of Information Technology. Electronic business(e-business) which is rapidly spreading throughout all industries has been initiated by the technological breakthrough of the digital revolution and rapid growth in the number of internet users. Shipping companies are increasingly taking up roles as integrated service providers to cope with the increasing demands of customers in the view of the new supply chain management(SCM) system. This will boost competitiveness, expand business opportunities and generate added value. Therefore most carriers have been implementing and updating their electronic data processing and networking in their overall liner businessmarketing analysis, cargo booking and traffic, container logistics, documentations, freight and disbursements, customers information etc., by providing integrated hardware and software.
(6) Other regulatory changes were made to the national policy of liner shipping by leading countries. Particularly in the United States, the Shipping Act of 1984 stipulates the allowance of the anti-trust exemptions for liner freight conferences along with the new introduction of Service Contract(SC) and Independent Action(IA) for shippers' interests. However the conferences were required to publicly post tariffs and negotiated individual contract with the FMC. In this regulatory environment not only did all carriers know exactly the terms of their partners' or rivals' freight rates but these were also visible to all shippers under the "me-too" clause of the law. Therefore any shipper could request the same rate as that negotiated for any other similarly situated shipper. Under these conditions, Conference carriers had extremely little incentive to deviate from the official conference tariff.
A remarkable momentum to change existing conservative in the freight market was the passage of the United States Ocean Shipping and Reform Act(OSRA) in 1998 which allowed shippers and carriers active in the US trades to enter into confidential contracts without prior notice. The result of this has been a rapid and massive switch to confidential agreements which have the potential to undermine the dominance of conference tariff. Very little traffic now takes place directly under conference terms. This movement was a decisive motive to let shippers have the power to negotiate lower rates whereas it underscored a generalized erosion of conference power.
In the case of the EU, in 1986 the European council of ministers adopted Regulation 4056/86 which provided a block exemption for liner conferences including common or uniform rates from Article 85 & 86 of the Treaty of Rome(EU Competition Rule) (now Article 81 & 82 as amended by the Amsterdam Treaty). However the European Shipper Council(ESC) and the OECD remains opposed to the liner conference block exemption, particularly the price fixing or rate setting provisions as liner shipping conferences do not provide freight stability or economic efficiency.
At the strong request of the ESC in 1996, the EU adopted the Consortia Rules, which precluded members of a consortium and vessel sharing agreements from fixing maritime price and inland transportation prices on the ground that the EC agreed that the liner consortia agreements were not liner conference. In 2000, EC reviewed the consortia block exemption and made some minor changes.
In Japan, Sec. 54 of Sea Transportation Law also stipulates an exemption of anti-trust law in respect of a convention, agreement, freight conference, etc., for the purpose of price fixing, cargo sharing, capacity adjustment in shipping industry. However it regulates that such exemption may not apply in case of serious problems by unfair transaction and competition.
In chapter 5, as the result of analysis of survey questionnaires by the Reliability Test Method and the Factor Analysis Method, it showed that the major factor of the determinant for liner freight rates is firstly change in Supply and Demand in ships capacity and secondly, the level of competition and conciliation among liner carriers, which is taking precedence over shipping costs. Of course, shipping cost is a fundamental factor in fixture of freight rate in normal market situations as described in the theoretical study of pricing determinant. However under the current situation of overtonnage, it cannot be classified as an independent variable.
Nowadays excess capacity in liner shipping is a result of increased competition among the carriers in which appears to have been led by a quest for lower freights and lower costs. In turn the liner market has been extremely unstabilized by the intense and unfair competition as the profitability of liner carriers has been reduced and such low profit may be the force driving liner carriers toward various strategies including alliances, mergers and building larger ships in an effort to capture economies of scale and scope. However most of carriers continue to be in difficult financial management, furthermore many of the liner carriers were pushed out of the world shipping markets.
Under such circumstances, this study is also concerned with how to stabilize for the liner markets and liner freight rates even though it is an extremely extensive and difficult task. The first order is to sum up the structural factors which dictate that not only carriers cannot receive a reasonable freight(rate) but that they also encounter constant pressure of freight decrease in current liner market is as follows:
(1)Mechanisms for maintaining the order and the stabilization in liner freight market was almost collapsed. Shipping conferences which traditionally had an oligopoly structure for the adjustment of fleet capacity and freight rates have no longer effectively exercised control in the current liner market.
(2)The excessive competition is widely spreadeel over among the carriers such as bargaining of freight, absorption of assorted charges and various malpractices in order to respectively slot utilization ratio.
(3)Shippers, especially big general trading houses and international freight forwarders/NVOCCs have become stronger negotiation (bargaining) power against the carriers through the abuse of their predominant position in a current excess capacity market.
(4)Whereas the power of collusive and cooperative actions among liner carriers becomes weaker, the current strategic alliance of the carriers is for survival and not for maintaining a stable freight market. Some competitive mega carriers are focusing on market domination through the increase of freight market share.
(5)The homogeneity of the quality of liner services is being accelerated through strategic ties and alliances with respect to service type, transit time, operation cost and marketing strategy.
Based on the aforementioned analysis and phenomena, the study presents some essential suggestions and recommendations, to stabilize liner freight rates and markets in both quantity and quality.
(1)The best optimization strategy for both carriers and shippers in liner shipping business is to maintain a stable and adequate freight rate without its rapid fluctuation as per supply and demand in the market. Accordingly it is necessary to establish an artificial and systematic mechanism in order for the carriers to provide general rules and tariffs with a self control policy. Therefore it is in the liner's best interests that a super conference, which modify past failure issues and participate in by all carriers trading in the same service route and accept anti-trust laws of relating countries, should be reformed quickly for the sake of freight restoration and stabilization. In this way, shippers will be able to easily predict future freight rate which will help lead towards the further stable transaction of international trade. Carriers, as well will, need to come up with appropriate master plans for fleet replacement and improvement in shipping services.
However it is very unfortunate that the Maritime Transportation Committee of the OECD recently reported that there are no reasons to allow exemptions from anti-trust laws for conference actions of the shipping business compared with other industries and instead call upon respective countries to review its rescission without any specific counter measures to the liner carriers.
(2) The priority subject for the stabilization of the freight and liner market is the reduction of excess loading capacity which has decisively led to the disorder of the liner trade and the decrease of freight rates. Accordingly it is desperately needed that an effective and enforceable measures should be taken to curb excessive investment to shipbuilding and to reduce existing excess vessel capacity in order to break the vicious cycle of irrationality in liner industry.
To be concrete, it is essential for them to set up and effectively manage an international institute or association for the purpose of i) constant study and circulation of ships capacity vs cargo movements, ii) strong recommendation of capacity adjustment, for which this study deliberately suggests that the International Maritime Organization(IMO) which is the standing organization of the ECOSOC in United Nations undertakes such research by the newly organized Vessel Adjustment Committee in addition to the existing five committees. This organization can expect to contribute positively to the overall global trading and shipping industry through their systematic and cooperative working channels to the respective nations and ocean carriers.
(3) Especially in the non-flexibility of the supply of ships, it is quite difficult for liner operators to make short term adjustment to ships space. In other words, in case of an increase of space requirement in the short run, the carriers were unable to meet cargo requirements due to the shipbuilding period of a few years in which the carriers are trying to cover their past loss in a time by adopting General Rate Increases(GRI) or General Rate Restorations(GRR) or charging Pick Season Surcharges(PSS) on existing freight. This also makes it difficult for shipper to do normal transactions because of unexpected increases in freight rates and fur the more This causes lots of friction with the carriers.
On the other hand, in case of decrease of cargo movement in a short period, the carriers cannot take any action either to suspend, independently, their liner services or lay up their fleets. Generally, most of liner carriers continue to do their service taking into account future good market and customer's relation.
Under such pressure, the carrier used to take to bargaining on freight rates and entering into service competition among the carriers by offering lower freight rates sometimes even marginal cost.
In respect to the above two cases in the short term period, the carriers or the alliances by themselves should take proper countermeasures such as adopting minimum box rates, vessel withdrawal schemes etc. to initiate reasonable freight decrease or increase through mutual cooperative action between carriers and shipper.
On the basis of the aforementioned theoretical and empirical study and analysis of the liner markets, it is clearly the conclusion that the determinant and change of liner freight rates have been influenced, on the most part, by supply of ships capacity and the competition of liner carriers.
Therefore, it is imperative for the liner shipping industry to control excess capacity of vessels and to stabilize liner freight rates by the mutual cooperative activities of the respective liner carriers and nations. For the purpose of effective and efficient implementation of these, it is profoundly considered that a systematical mechanism such as Super Conference in major liner trade and the Capacity Adjustment Committee of the executive organization of U.N. shall be restructured as soon as possible.
Lastly, all the other business industries and international commercial organizations should actively support the liner shipping industry to stabilize the liner market and freight rates and to fulfil, satisfactorily, the mission of common/public carriers in worldwide trade.
Meanwhile the subject of this study is very extensive, profound and variable in accordance with the prevailing market environment, thus more rigorous studies are constantly needed to improve the liner market and the liner industry.목차
第1章 序論
第1節 硏究의 背景 및 目的 = 1
第2節 硏究의 方法 및 範圍 = 3
1. 硏究의 方法 = 3
2. 硏究의 範圍 = 4
第2章 定期船海運의 特徵과 海運環境 變化
第1節 定期船海運의 特徵 = 6
1. 海運의 意義 = 6
2. 定期船 海運市場의 意義 = 8
3. 定期船海運의 特徵 = 8
第2節 定期船海運의 環境變化？？ 展望 = 10
1. 定期船海運의 對外的 環境變化 = 10
2. 定期船海運의 對內的 與件變化 = 16
第3章 定期船海運의 運賃決定에 관한 理論的 考察
第1節 海上運賃決定에 관한 一般理論 = 48
1. 生産費說 = 49
2. 用役價値說 = 49
3. 負擔能力說 = 50
4. 折衷說 = 51
第2節 定期船 運賃決定에 관한 傳統理論 = 52
1. 獨占理論 = 52
2. 補完理論 = 55
3. 傳統理論의 限界 = 59
第3節 定期船 運賃決定에 관한 新理論 = 60
1. 競合市場理論의 意義 = 60
2. 競合市場의 特性과 政策的 示唆點 = 63
3. 競合市場理論의 限界 = 67
4. 競合市場理論과 定期船 市場分析 = 69
第4節 定期船 運賃決定의 實務的 考察 = 77
1. 供給者(船社)의 運賃決定 方法 = 78
2. 서비스 利用者의 運賃決定 方法 = 80
3. 서비스 地域別 運賃決定 方法 = 82
第4章 定期船 費用構造와 運賃構造
第1節 定期船 費用構造 = 86
1. 資本費 = 86
2. 運航準備費 = 87
3. 運航費 = 89
第2節 허브포트와 멀티포트 運航간의 費用構造 = 93
1. 定期船社의 費用構造에 관한 새로운 接近 = 94
2. 컨테이너船舶의 費用 模型 = 95
第3節 定期船 運賃構造 = 102
第5章 定期船 海運市場의 運賃決定 要因에 관한 實證分析
第1節 國籍外航船社의 定期船 海運環境 實態調査分析 = 109
第2節 定期船 海運市場에서 運賃에 影響을 미치는 要因 = 112
第3節 硏究模型과 硏究假說 = 113
1. 硏究模型 = 113
2. 硏究假說 = 114
3. 變數의 選定과 測定 = 115
4. 運賃決定要因과 運賃變動 및 成果간의 關聯性 分析結果 = 118
第6章 定期船運賃 安定化方案
第1節 定期船運賃 安定化의 必要性 = 128
1. 글로벌 海運物流네트워크 構築基盤 强化 = 128
2. 定期船 海運市場의 構造的 不安定에 대한 核心 對應課題 = 130
第2節 定期船海運의 運賃安定化 方案 = 136
1. 運賃安定化 問題와 主要國 獨禁法과의 關係 = 136
2. 運賃安定化 方案 = 143
第7章 結論 = 156
<參考文獻
A Study on Design of ARM Processor based Fingerprint Recognition Signal Processing Board using Artificial Intelligence
Full text linkFingerprint is a unique feature to an individual. It stays with a person throughout his or her life. This makes the fingerprint the most reliable kind of personal identification because it can't be forgotten, misplaced, or stolen.
Now, social requirements of personal identification techniques are expanding in a number of new application area. Especially fingerprint recognition technologies among biometrics technologies has more spot lighting beacuse fingerprint authorization is the most profitable and convenient method of Biometric Authentics System(BAS).
Generally, BAS is classfied into PC(personal computer) BAS and Standard-alone BAS. PC-BAS is only designed for using into computer and Standard-alone BAS(S-BAS) represents independent system of using microprocessor.
In this paper, neural network was used(one for core and another for delta)in feature extraction and the processor of designed Fin-gerprint identification Signal processing Board(FSB) used SA(St-rongARM), it was used into network, set-top box, PDA(Perso-nal Digital Assistant), PCS(Personal Communications Services), etc. and in the most BAS, fingerprint sensor uses optics sensor but in this paper, fingerprint sensor used cmos E-Field type.
After test, designed S-BAS proved that it is possible to imp-lement independently whitout PC.목차
Abstract = i
제1장 서론 = 1
제2장 신경회로망 = 3
2.1 신경회로망 이론 = 3
2.2 역전파에 의한 학습 = 6
제3장 지문인식 알고리즘 = 12
3.1 전처리(Preprocessing) = 12
3.2 특징 추출 = 15
3.3 지문영상의 매칭(Matching) = 18
제4장 지문인식 신호처리 보드 설계 및 실험 = 20
4.1 CPU 부분 = 20
4.2 센서 부분 = 28
4.3 지문인식모듈 구성도 = 38
4.4 FAR과 FRR = 38
4.5 실험 결과 = 39
제5장 결론 = 49
참고문헌 = 50
부록(APPENDIX)
A. 메인 회로도 = 52
B. 센서 회로도 = 53
C. 지문인식 신호처리보드의 실제 크기 = 54
D. 지문인식 신호처리보드의 Gerber = 5
A Dynamic Analysis of Tension-Legged Circular Cylinder in Irregular Waves
Full text linkThe technology development for ocean resources can be represented by the increase of water depth. TLP, Tension Leg Platform, is one of the most feasible systems for deep sea development. TLPs show a complex dynamic behavior resulting from the dynamic interactions among platform, tether system and riser system due to their hydrodynamic and structural dynamic characteristics in waves.
This thesis aims at the theoretical and experimental analysis on motion response of TLP in waves. It is composed of three parts as follows : (1) wave and wave loadings (2) TLP motion (3) TLP tether tension목차
Abstract = I
Nomenclatures = IV
List of Tables = VIII
List of Figures = IX
1. 서론 = 1
1.1 연구의 배경 = 1
1.2 기존의 연구 = 3
1.3 연구의 내용 = 4
2. 이론해석 = 7
2.1 개요 = 7
2.2 선형 및 비선형 파강제력의 해석 = 9
2.2.1 자유표면 경계조건 = 10
2.2.2 물체표면 경계조건 = 12
2.2.3 경계치 문제와 유체력 = 16
2.2.4 파강제력과 전달함수 = 19
2.2.5 운동방정식 = 29
2.3 시간영역에서의 응답 해석 = 31
2.3.1 시간영역에서의 파강제력 = 31
2.3.2 시간영역 운동방정식 = 38
2.4 계류력의 해석 = 40
2.5 이론계산 결과 = 42
2.5.1 규칙파중의 파강제력 = 42
2.5.2 각 운동 모드에 대한 임펄스 응답함수 = 43
2.5.3 불규칙파중의 파강제력 = 44
2.5.4 과도수파중의 파강제력 = 46
3. 실험 및 TLC 모델 = 48
3.1 실험방법 및 조건 = 48
3.2 TLC 모델 = 49
3.3 실험장면 = 51
3.4 실험 데이터의 계측 및 처리 = 53
4. 실험결과 및 고찰 = 57
4.1 규칙파중의 응답해석 = 58
4.2 불규칙파중의 응답해석 = 64
4.3 과도수파중의 응답해석 = 68
4.3.1 과도수파의 재현 = 68
4.3.2 응답해석 = 68
5. 결론 = 74
참고문헌 = 7
Development of a Human-Sized Biped Walking Robot
Full text linkIn this thesis, I present research results on a human-sized biped walking robot(BWR). The BWR was developed to walk autonomously such that it is actuated by small torque motors and is boarded with DC battery and controllers. The BWR is driven by a new joint actuator based on the ball screw which has high strength and high gear ratio. Using a small DC motor. The joint actuator is composed of 4-link bar actuated by the ball screw. The robot overcomes the limit of the driving torque of conventional BWRs. Each leg of the robot composes of three pitch joints and one roll joint. In all, a 10 degree-of-freedom robot with two balancing joints was developed. The motor drive and data interface system is developed. To develop BWR, I performed an analysis on the kinematics and dynamics of the BWR. In the performance test, the BWR performed motions of sitting-up and sitting-down. Through a set of experiments, we could find capability of high performance in biped-walking.Abstract
사용기호
표목차
그림목차
Ⅰ. 서론 = 1
Ⅱ. 관절구동기의 동역학 해석 = 4
2.1 발목관절의 동역학 방정식 = 6
2.2 무릎관절의 동역학 방정식 = 10
2.3 힙관절의 동역학 방정식 = 13
Ⅲ. 다리의 동역학 모델링 = 16
3.1 회전관절 공간상에서의 다리의 운동방정식 = 17
3.2 미끄럼관절 공간상에서의 다리의 운동방정식 = 19
3.3 10자유도 이족 보행로봇의 구성 = 21
Ⅳ. 제어부 = 23
4.1 제어기 = 24
4.2 인터페이스 장치 설계 제작 = 27
4.2.1 변환기 설계 = 29
4.2.2 PWM 발생기 설계 = 29
4.2.3 Dead Time 발생기 설계 = 30
4.2.4 센서신호 전달부 설계 = 31
4.2.5 전원분리부 설계 = 32
4.3 서보모터 구동부 설계 = 33
Ⅴ. 보행실험 및 고찰 = 36
Ⅵ. 결론 = 50
참고문
A Study on the Development of a Non-Destructive Test System by a Magnetic Flux Leakage Method
Full text linkIn this research, the development of a Non-Destructive Test (NDT) system by a Magnetic Flux Leakage(MFL) method is presented.
The detection of a crack or defect of a gas pipe is very important in management of a gas pipe. The sensing equipment, so called PIG, is commonly used to detect defects of the underground gas pipe. The system is consisted of magnetic yoke, Hall sensors and gas pipe.
in the system, the magnetic field produced in permanent magnet is guided to the gas pipe by brush and magnetic yoke. The Hall sensors detect the leakage flux in the region of defects such as crack, corrosion, wrinkle, buckle and so on.
The defect signals in a MFL type NDT system mainly depend on the change of the magnetic leakage flux in the region of a defect. So, the optimum system was designed to maximize the magnetic leakage flux in that region and the results are compared with experimental measurements.목차
Abstract
제 1 장 서론 = 1
1.1 연구배경 = 1
1.2 MFL PIG의 구조 = 3
제 2 장 MFL PIG 시스템의 전자기적 해석과 최적 설계 = 5
2.1 MFL PIG 설계 = 6
2.2 MFL 결함 해석을 위한 유한 요소법 = 8
2.2.1 지배 방정식 = 8
2.2.2 정식화 = 10
2.3 브러시의 투자율 = 12
2.4 MFL PIG의 비선형 해석 = 13
2.5 MFL PIG의 2차원과 3차원 해석 = 15
2.6 가스관 적정 포화 설계 = 17
2.7 센서의 민감도 향상 = 22
제 3 장 가스관 결함에 의한 MFL PIG 검출 신호 해석 = 24
3.1 MFL PIG의 defect가 있을 경우 3차원해석 = 24
3.2 MFL PIG의 센서 방향에 따른 검출신호 = 25
3.3 MFL PIG의 defect 깊이 영향 = 29
3.4 MFL PIG의 defect 크기 영향 = 30
3.4.1 기준 defect 해석 = 30
3.4.2 결함의 폭이 커질 경우 = 32
3.4.3 결함의 길이가 길어질 경우 = 34
3.4.4 결함의 폭과 길이가 모두 커질 경우 = 36
제 4 장 결론 = 38
참고문헌 = 4
A Study on Design of Ferrite Electromagnetic Wave Absorber with Wide-Band Characteristics for the Use of Anechoic Chamber
Full text linkRecently, the use of equipments related to information communication has increased drastically. Since unnecessary electromagnetic waves are radiated from electronic equipments and systems, it is reported that the mall function of the equipments and some fatal damage to human life occur.
For the countermeasure to the above, several regulations for the electromagnetic wave interference, have been enacted internationally by CISPR, FCC, ANSI, etc.
In the domestic case, the regulations related to the Electromagnetic Interference (EMI) and the Electromagnetic Susceptibility (EMS) have been established and enacted. For measurement of such EMI and EMS, an equivalent, free space from electromagnetic waves are required. As the means of the equivalent space, an anechoic chamber is widely used.
The Frequency range for EMI test was from 30MHz to 1GHz. However it was broadband from 1GHz to 18GHz additionally by CISPR 11 on November, 1998.
To construct in anechoic chamber for the above purpose, it is needed that the electromagnetic wave absorber has the capability to absorb the EM wave more than 20dB over the frequency band.
The ferrite tile in a single layer type has been used, the frequency band of which is about 30MHz ~ 400MHz, with more than 20dB of absorption capability. In the case of a grid type absorber developed by Y. Naito, the frequency range to satisfy the above absorption characteristics is approximately from 30MHz ~ 870MHz. Thus it was not sufficient to satisfy the above condition.
Accordingly, in this dissertation, in order to satisfy the above demand, the electromagnetic wave absorbers with wide band characteristics was proposed by controlling shape and dimension. The proposed electromagnetic wave absorber in cutting cone-shaped one is of less than 5cm in thickness. The bandwidth of the proposed absorber is from 30MHz to 6GHz, which was designed by the EMCM and confirmed by simulation and experiments.
As a measuring method of the absorption characteristics of the ferrite electromagnetic wave absorber, tapered rectangular coaxial line, was fabricated and used, which has 50Ω adapter with l3/8 in diameter.
In addition, the characteristics of the anechoic chamber by the proposed cross-shaped absorber were evaluated be the image method. They were compared with those of the OATS.목차
Nomenclature = iv
Abbreviations = vi
Abstract = vii
제1장 서론 = 1
1.1 연구배경 = 1
1.2 연구 목적 = 3
1.3 연구 방법 = 5
제2장 전파흡수체 설계 이론 = 7
2.1 전파흡수체의 분포정수회로화 = 7
2.1.1 파동방정식(Helmholtz Equation) = 7
2.1.2 분포정수회로화 = 13
2.2 전파흡수체 재료와 측정 = 20
2.2.1 손실재료 = 20
2.2.2 재료의 측정법 = 29
2.3 등가재료정수법에 의한 전파흡수체 해석 = 37
2.3.1 페라이트 전파흡수체의 주파수 분산 특성 = 37
2.3.2 등가재료정수법 = 45
제3장 광대역 페라이트 전파흡수체의 설계 및 특성 = 54
3.1 타일형 및 그리드형 페라이트 전파흡수체 = 54
3.1.1 수직입사(垂直入射) 특성과 ？瑛犢？(斜入射) 특성 = 54
3.1.2 타일형 및 그리드형 전파흡수체 = 64
3.2 십자돌기형 페라이트 전파흡수체 = 66
3.2.1 십자돌기형 페라이트 전파흡수체의 설계 = 66
3.2.2 십자돌기형 페라이트 전파흡수체의 성능평가 = 71
3.3 원추절단형 페라이트 전파흡수체 = 79
3.3.1 원추절단형 페라이트 전파흡수체의 설계 = 79
3.3.2 원추절단형 페라이트 전파흡수체의 성능평가 = 82
제4장 십자돌기형 페라이트 전파흡수체의 전파반무향실(電波半無響室) 특성 평가 = 85
4.1 전파반무향실 이론 = 86
4.1.1 시험장 이론 = 86
4.1.2 상호결합(Mutual Coupling) = 96
4.1.3 하이트 패턴(Height Pattern) = 103
4.2 타일형 및 그리드형 전파흡수체를 적용한 전파반무향실의 특성 = 108
4.2.1 타일형 및 그리드형 전파흡수체의 입사 특성 = 108
4.2.2 시험장 감쇠량 = 109
4.2.3 시험장감쇠량의 계산치와 실측치의 비교 = 119
4.2.4 상호결합을 고려한 시험장감쇠량 = 123
4.2.5 수평편파와 수직편파간의 시험장감쇠량 비교 = 126
4.3 십자돌기형 전파흡수체를 적용한 전파반무향실의 특성 = 129
4.3.1 십자돌기형 페라이트 전파흡수체 특성 = 129
4.3.2 시험장 감쇠량 = 129
4.3.3 타일 및 그리드형과 십자돌기 전파흡수체를 적용한 전파반무향실의 특성 비교 = 138
제5장 전파흡수체의 흡수능 측정 = 139
5.1 동축관에 의한 전파흡수능 측정기법 = 140
5.1.1 전파흡수능 측정기법의 종류 = 140
5.1.2 동축선로의 임피던스 해석 = 144
5.2 테이퍼 구형 동축관 측정시스템 제작과 측정 = 153
5.2.1 구형동축관을 이용한 흡수능 측정시스템의 구성 = 153
5.2.2 구형동축관을 이용한 흡수능 측정 = 161
제6장 결론 = 166
참고문헌 = 16
Three-dimensional acoustic radiation from directional cracks in fluid-loaded plate based on Global Matrix Method
Full text linkThree-dimensional acoustic radiation
from directional cracks in fluid-loaded plate based on Global Matrix Method
The formation of crack in elastic media such as fluid-load plate generates elastic waves in a radiation pattern being dependent on the actual fracture process and the stratification of medium. In case of horizontal stratification, this phenomenon can be idealized and mathematically modeled describing the directionality of the acoustic emission produced by compact cracks in such an environment.
The object of the research has been to develop an analytical and numerical model of the elastic wave field in range independent elastic environments for various seismic source mechanisms. The source types being considered are dip slip, strike slip and tensile crack. First, the compact source representations with fault surface in an arbitrary direction will be derived, and incorporated in a numerical model for propagation in stratified elastic media to yield the seismo-acoustic field produced by more complete cracking mechanisms.
The developed model is applied to the acoustic radiation from three directional crack in fluid-load plate. The developed model can be applied to the source inversion problem, i. e. the characterization from acoustic emission with the purpose of obtaining a better understanding of the ocean structure of self noise in fluid-load plate