Earticle

무인항공기는 2000년대 중반부터 탐색, 조사, 매핑, 수색 및 구조 등의 3D 작업에 적극적으로 사용되기 시작했다. 이러한 세계적인 추세에 따라, 무인항공기의 정밀한 제어는 엄청난 응용 산업들의 측면에 있어서 혁명을 가져올 것이다. 논문의 첫 번째 파트에서는 시스템식별 기법을 사용하여 간략화 된 무인항공기의 모델을 이전의 이산시간 선형모델과 비교분석 한다. 두 번째 파트에서는 동적 모델의 세 가지 변수가 배치추정기법과 RLS추정기 법을 사용하여 추정된다. 쿼드로터 무인항공기 호버링 기동 시의 각가속도 데이터가 항상 수렴한다고 분석되었다. 또한 실험 및 MATLAB 시뮬레이션의 쿼드로터 무인항공기 비행 데이터에 의하면, 배치추정기법이 RLS추정기법 보다 더 정확하다고 판명되었다.

UAVs began to be actively applied to so-called 3D jobs, including the autonomous exploration, investigation, mapping, search and rescue, etc. since the mid-2000s. With this global trend, having a precise controllability of the UAV will certainly revolutionize the life of the modern human in the aspect of tremendous applications of the UAV. In the first part, a simplified dynamic model of the UAV identified using system identification techniques is compared with the previously built time-discrete linear model. In the second part, the three parameters of the dynamic model are estimated using the batch and RLS methods. Angular acceleration data of the quadrotor UAV at the hovering maneuver are analyzed and shown to be converging at all time. Also, according to the quadrotor flight data from both experiments and MATLAB simulations, the batch estimation method turns out to be more accurate than the RLS estimation method based on the comparison of final parameter values.

농림축산식품부에서는 내재해형 규격 설계도 및 시방서를 보급하여 농민들을 지원코자 하고 있으나, 전 세계적인 이상기후 현상과 더불어 접합부의 구조적 성능 및 골조 경량화에 따른 비닐하우스 붕괴 피해는 점차 늘어나고 있다. 이러한 붕괴양상에 대응하기 위해서는 비닐하우스의 시스템 식별에 따른 동특성 파악이 필수적이다. 시스템 식별은 현장 계측에서 수집한 데이터를 이용하여 SSI기법을 통해 수행하였다. 데이터 수집에는 가속도계 및 데이터 로거를 이용하였으며, 규격 설계도에 따른 기존형과 몇몇 개선을 거친 대안형 비닐하우스를 대상으로 계측을 수행하였다. 1차 모드 고유진동수는 기존형과 대안형 비닐하우스 각각 약 3.65 Hz, 약 3.21 Hz로 나타났다. 1차, 2차, 3차 모드 순으로 모드형상 분석 결과, 기존형 비닐하우스가 x축, y축, torsion, 대안형 비닐하우스는 y축, torsion, x축 병진 방향의 모드형상이 파악되었다. MIDAS Gen을 이용한 유한요소해석과의 비교 결과, 모드형상은 동일하게 나타났으며, 고유진동수 추정에는 상당한 오차가 발생하였다. 접합부 및 지점조건 설정에 관한 추가적인 연구가 요구된다.

Ministry of Agriculture, Food and Rural Affairs(MAFRA) has disseminated Design and specifications of standardized anti-disaster prototypes for greenhouses to farmers for supporting them, but the number of structural failures of greenhouse is increasing due to worldwide abnormal climate, structural performance of connections and weight lightening of framework. Therefore, it is essential to understand dynamic performance of greenhouse through system identification. System identification was conducted using SSI method by data from field measurement. Field data were acquired using accelerometers and data logger, prototype greenhouse following the design and specifications of standardized greenhouse and alternative greenhouse been through structural improvement were chosen as specimens. 1st mode natural frequency of prototype and alternative greenhouse was shown that 3.65Hz and 3.21Hz, respectively. Analysis result about mode shapes is that mode shapes of prototype are translational modes in the x-, y-axis and rotational mode in order, them of alternative are translational mode in y-axis, rotational mode and translational mode in x-axis in order. FE models analysis for both greenhouses showed that there exist considerable errors in the natural frequencies. Therefore, it is necessary to additional study about connections and supports of greenhouse in FE modeling. In case of mode shapes, FE models analysis results are coincide with the results from field measurement.

지진동을 받는 기존 구조물에 외부 에너지를 투입하여 변위를 제어하는 능동제진의 경우에, 제어설계의 비용감소 및 시스템의 불안정상태를 방지하기 위해 구조물의 동적특성을 파악하는 것이 매우 중요하다. 구조물의 동적 특성을 파악하기 위해 입력에 따른 출력을 실험적으로 계측하는 시스템규명이란 방법을 적용해 볼 수 있다. 시스템 규명은 전자 및 기계공학 분야에서 적용되오던 방법으로, 건축구조물과 같은 대형시스템의 지진동제어를 위해 이 방법이 적용가능한지 실험적으로 검증해보는 것이 연구의 목적이다. 실험 결과에 의하면 시스템 규명은 적용가능하며, ARMAX 모델이 ARX, ARMA 보다 효과적임을 확인할 수 있었다.

The dynamic characteristics of the structure must be understood in order to design an efficient active seismic controller. Evaluating the parameters with precision is very crucial not only for accomplishing a low cost controller, but for preventing the structural control system from unstable behavior. These characteristics of the structures can be estimated from the measured input-output data called the system identification. The purpose of the study is to evaluate the feasibility of the system identification method used in mechanical and electrical engineering applications to apply for the building structures subjected to seismic disturbance. The results of the study show that the system identification method is effective for determining the dynamic characteristics of the building structure, and ARMAX model is the most feasible one among ARMAX, ARX and ARMA.

The dynamic characteristics of the structure must be understood in order to design an efficient active seismic controller. Evaluating the parameters with precision is very crucial not only for accomplishing a low cost controller, but for preventing the structural control system from unstable behavior. These characteristics of the structures can be estimated from the measured input-output data called the system identification. The purpose of the study is to evaluate the feasibility of the system identification method used in mechanical and electrical engineering applications to apply for the building structures subjected to seismic disturbance. The result of study that ARX model, ARMA model, ARMAX model can be suitable model to apply for building structure in the system identification.

The dynamic characteristics of the structure must be understood in order to design an efficient active seismic controller. Evaluating the parameters with precision is very crucial not only for accomplishing a low cost controller, but for preventing the structural control system from unstable behavior. These characteristics of the structures can be estimated from the measured input-output data called the system identification, and then the dynamic behavior of structure can be thoroughly analyzed though a computer simulation, which leads to the way to come up with an excellent controller. The purpose of the study is to evaluate the feasibility of the system identification method used in mechanical and electrical engineering applications to apply for the building structures subjected to seismic disturbance. The results show that the model behaves sensitively with respect to the lambda values. ARMA and ARMAX model showed relatively stable estimating performance against changes of the lambda values, and superior estimating performance under the same value of the lambda comparing to ARX. The conclusion is that the ARMAX model can be the most suitable one to apply for building structure in the system identification.

본 연구의 목적은 주기적 모니터링을 통해 부유식 콘크리트 구조물의 구조 건전성을 평가하는 것이다. 실제 부유식 콘크리트 구조물을 대상으로 주기적 모니터링을 실시하여 동적 특성을 추출하였다. 추출된 동적 특성과 수치해석 모델을 이용하여 다음 두 가지 활동을 통해 구조 건전성을 평가하였다. 먼저, 비파괴 손상 평가기법을 이용하여 손상의 발생 및 진전을 평가하였으며, 균열도와의 비교를 통하여 그 결과의 신뢰성을 검증하였다. 다음으로, 구조계 추정기법을 이용하여 강성 저하 추이를 분석하였다. 그 결과로, 구조물의 요구 성능 확보여부를 판단할 수 있었다.

The objective of this study is to evaluate the structural integrity of the floating concrete structure through periodic monitoring. Dynamic characteristics of the actual floating concrete structure were extracted from the periodic monitoring. The structural integrity using the extracted dynamic characteristics and numerical model was evaluated by the following two activities. First, the structure damage was evaluated for occurrence and progress using the damage detection method. The reliability of the results was verified by comparison with the crack drawing. Second, the stiffness degradation trend was analyzed using the system identification method. As a result, the structural satisfy performance criteria and safety.

18층 사무실용도 건물(SIB)의 동적성능을 결정하기 위하여 자연 진동계측 실험을 수행하였다. 해당건물은 기본적으로 철골골조 형식이나, 보다 효율적으로 수평하중을 지지하기 위하여 콘크리트 코아가 추가된 복합 구조형식을 취하고 있다. 계측된 일련의 진동기록에 최신 주파수- 및 시간영역-기반 응답의존 시스템판별법인 FDD, pLSCF 및 SSI를 적용하여 모달계수를 추출하였다. 3방법에 의하여 추출한 결과는 대체로 일치하였으나, 초기 3D-FE 해석결과와 비교하여 저차 3개 고유진동수는 대략 1.1~1.6배 정도의 단단한 거동을 나타냈다. 진동실험 및 FE 해석으로 부터 획득한 고유진동수 및 모드형태와 같은 모달계수의 일치를 위하여 최적화이론에 근거한 자동모델향상을 시도하였다. 자세한 3D-FE모델의 해석결과로부터 매 층 마다 3개의 강성 및 3개의 질량을 변수로 갖는 단순 FE모델을 유도하여 모델향상의 시작모델로 사용하였다. 일치를 시도한 6개의 모드 중 저차 3차 모드까지만 고려한 향상된 FE모델은 자연진동수 및 모드형태에 대하여 우수한 일치를 나타냈다. 모델향상을 수행한 결과에 의하면, 현재의 국내 FE 구조해석 실무는 층강성 및 층질량을 각각 다소 과소 및 과다하게 고려하고 있는 것으로 판단된다.

Dynamic response measurements from natural excitation were carried out for a 18-story office building(SIB) to determine its inherent properties. A steel beam-column frame system was adopted as a typical structural form, but a concrete core wall was added to resist the lateral force more effectively, resulting in a mixed configuration. The most advanced operational system identification methods based on frequency- and time-domain like FDD, pLSCF and SSI were used to extract modal parameters form a series of vibration records. The frequencies and mode shapes extracted from different identification methods showed a greater consistency, however the three lower frequencies exhibited 1.1 to 1.6 times as stiff as those obtained using a detailed 3D-FE model. Automatic FE model updating adopting optimization theory was applied to correlate experimental and analytical modal parameters such as natural frequencies and mode shapes. The simplified FE model containing 3 stiffnesses and 3 masses at each story as structural parameters derived from a detailed 3D-FE model was used as a starting one for updating. The excellent match between test and analytical modal parameters was made for the lower three modes out of the six. Based on the updating results, it can be judged that the domestic design practice for FE analysis somewhat underestimates the story stiffness, while overestimating the story mass.

시스템 식별기법은 구조물의 계측응답을 이용하여 현재 상태를 정량적으로 평가하기 위한 기술로써, 구조해석, 내진 및 내풍성능 평가, 진동제어 등 다양한 분야에 적용되고 있다. 특히, 구조해석분야에서는 모드특성 이외에 구조물의 질량, 감쇠 및 강성계수 등 물리적인 의미를 갖는 변수들을 직접 추정할 필요가 있다. 본 연구에서는 구조물의 계측된 진동수 응답함수를 이용하여 동적해석모델을 구성하는 요소들인 질량, 감쇠 및 강성계수를 직접 추정하는 기법을 제안하였다. 이러한 계수들을 시스템식별 변수로 하는 동적해석모델을 구성하고 이로부터 유도된 진동수 응답함수와 계측된 진동수 응답함수의 크기와 위상에 대한 오차의 제곱을 성능지수로 정의하고, 이를 최소화시킴으로써 질량, 감쇠 및 강성계수를 추정하였다. 구조물의 거동을 정확히 묘사할 수 있는 동적해석모델이 구성되면, 질량, 감쇠 및 강성계수를 정확히 추정할 수 있다는 것을 수치시뮬레이션으로 검증하였으며, 구조물의 모드특성은 식별된 동적해석모델로부터 계산된다.

System identification technique has been applied to various fields of structural analysis, evaluation for seismic- and wind-resistant performance of structures and structural control, with which current state of a structure is quantitatively evaluated by using measured structural responses. Especially, in addition to modal properties of a structure, variables including physical meaning such as mass, damping and stiffness coefficients are required to be estimated directly in structural analysis. This paper proposes the system identification technique, with which mass, damping and stiffness coefficients of a dynamic analytical model are estimated by using measured frequency response function of a structure. The square of error for amplitude and phase between two transfer functions was defined as performance index for minimization. One is the transfer function measured from structural dynamic test, and the other is that derived from a dynamic analytical model with mass, damping and stiffness coefficients, which are defined as variables for identification. It was verified from numerical simulation that mass, damping and stiffness coefficients can be estimated precisely, if only a structure is modelled exactly for its behavior. Structural modal properties were calculated from the identified dynamic analytical model.

The purpose of this study is to analyze the zero frequencies of the frequency response functions(FRFs). The peaks in FRFs represent the natural frequencies of the structure and the zeros provide additional information. The characteristics of peaks and zeros are defined and the calculation procedure to obtain the peaks and zeros from the relationship between frequency response function and stiffness and mass matrices are clearly explained. A system identification technique is presented using peak and zero frequencies and a damage detection example via a spring-mass system is provided.

Is not used by consistency transport at transport of freight nothing but is using Pallet only by pedestal when work palletized unit load or materials handling when keep simplicity receptacle which fill raw material or product in factory in our country. Therefore, pallet that is most important function of Pallet is not empled circulation to end consumer from manufacturing plant which is circulation process whole path being done and factory. It is real condition stopping only in extremely determinate part process use of warehouse back. Additionally, it is possible to figure out the flow of all the materials loaded on the RFID pallet; product, material, raw material immediately, so that epoch-making management is possible and it contributes to the reduction of logistics cost because there are little loss or outflow of pallet. The materials flow is getting speedy and inventory is decreasing in the logistics process, and also bad inventory and loss problems are prevented. As a result, not only logistics cost of company but also national logistics cost is decreased. Thus it contributes to the strength of national competitiveness.

본 연구는 전자식별칩(RF-ID)를 활용한 생산이력추적 시스템을 도입하여 가축의 생산, 도축, 가공 및 유통단계에 있어 효율성을 증진시키고 소비자들에게 질 좋고 위생적인 한우육을 제공할 수 있도록 발전시키기 위하여 수행하였다. 생산이력추적 시스템의 기본이 되는 새로운 개체식별 바코드, 등록번호 및 농장번호를 고려하여 관리, 자료의 수집과 저장이 용이하도록 설계되었다. 특히 이 시스템은 1) 가축관리를 위하여 표준 전자 식별칩(RF-ID), 표준이표, 마이크로칩 그리고 이표식별 장비를 제공하고, 2) 한우육 상표 보장을 통해 소비자를 보호하고 3) 품질 좋은 한우육을 생산하는 농가에게 인센티브를 제공하고 4) 국가적 개체관리에 있어 획일한 시스템을 제공하는데 그 목적이 있다. 몇몇 농가조합에 적용한 결과와 모 백화점에서 실시한 시범사업 결과 RF-ID 시스템 사용에 대한 가능성을 볼 수 있었다.

This study was conducted to develop a traceability system for systematic animal identifi- cation to increase efficiency of animal production, post production and processing to ensure that quality and sanitary meat products reach the consumers of the entire country. The new animal identification traceability system was designed for easy management, data collection and storage considering bar code, registration number and farm number.Specifically the system aimed 1) To provide standard radio frequency technology identification (RF-ID) for livestock management, standard of ear tag, microchip and ear tag identification equipment, 2) To guarantee meat product label thereby safeguarding the consumers 3) To give incentives to farmers for producing quality meat products and 4) To provide unified system for national livestock management.Results of the research which started in July 2003 which was used by several farmers’ cooperatives and Department Store revealed the feasibility of using the RF-ID system although much will be done to conform to global nomenclatures.

Background: The present study was intended to determine the prevalence and identification of species involved causing coccidiosis in broilers rearing under traditional farming system in Mirpur, Azad Kashmir, Pakistan. For the current study, a convenient sampling technique was carried out. A total of 7814 broilers (aged 1 to 6 weeks) were submitted to the Disease Diagnostic Laboratory of Livestock and Animal husbandry Department Mirpur, Azad Kashmir. Results: From the total screened, 750 were found positive for coccidiosis representing an overall prevalence of 9.59 %. Age-wise highest prevalence (10.88 %) recorded in the middle age birds (0 to 3 week old) were found more susceptible to infection than those aged above 3 weeks. Higher prevalence (12.49 %) of coccidiosis in broilers was observed in spring as compared with 6.60 % in summer season. In this study two main coccidiosis causing species, Emeria tenella and Emeria maxima were identified on the basis of their morphological feature and habitat (caeca and intestine), However, E. tenella was dominant compared to E. maxima. Conclusion: The study provides an insight to the occurrence of Emeria species which must be taken into consideration when rearing the broilers.

This paper presents the data-driven modeling based on recurrent neural network (RNN) for the system identification of vehicle dynamics. For the accurate control of an autonomous vehicle, a sophisticated model of the vehicle dynamics is required. Data-driven modeling can achieve such a model only with the data obtained from the target. A simulation result by using the data from a driving simulator is included to test the feasibility of the RNN for the system identification of a ground vehicle.

This study is aimed at exploring ideas for the development of Pilates in-structor qualification system by identifying a range of difficulties Pilates instructors are experiencing. Open-ended questionnaires and semi-structured interviews were conducted to collect data before they were analyzed with inductive content analysis method. In consideration of the difficulties Pilates instructors experience during three qualification stages (before-during-after qualification education), three key catego-ries were incorporated in the collected data: (1) lack of information on Pilates qualification system, (2) difficulties in understanding the human anatomy related with the diverse movements taught in Pilates classes and its application to Pilates practice, (3) need for professional develop-ment through retraining. Based on these findings, a need for rethinking the monitoring and evaluation process for Pilates qualification system and Pilates education in Korea was identified. In addition, we need to summarize and offer information on a range of Pilates qualifications. And the quality of Pilates instructor education program should be im-proved as well by proving them a range of teaching methods including microteaching, discussion-based lessons as well as reading and writ-ing sessions and other necessary teaching media.

Background: Radiation portal monitors (RPMs) involving plastic scintillators installed at the border inspection sites can detect illicit trafficking of radioactive sources in cargo containers within seconds. However, RPMs may generate false alarms because of the naturally occurring radioactive materials. To manage these false alarms, we previously suggested an energy-weighted algorithm that emphasizes the Compton-edge area as an outstanding peak. This study intends to evaluate the identification of radioactive sources using an improved energy-weighted algorithm. Materials and Methods: The algorithm was modified by increasing the energy weighting factor, and different peak combinations of the energy-weighted spectra were tested for source identification. A commercialized RPM system was used to measure the energy-weighted spectra. The RPM comprised two large plastic scintillators with dimensions of 174 × 29 × 7 cm3 facing each other at a distance of 4.6 m. In addition, the in-house-fabricated signal processing boards were connected to collect the signal converted into a spectrum. Further, the spectra from eight radioactive sources, including special nuclear materials (SNMs), which were set in motion using a linear motion system (LMS) and a cargo truck, were estimated to identify the source identification rate. Results and Discussion: Each energy-weighted spectrum exhibited a specific peak location, although high statistical fluctuation errors could be observed in the spectrum with the increasing source speed. In particular, 137Cs and 60Co in motion were identified completely (100%) at speeds of 5 and 10 km/hr. Further, SNMs, which trigger the RPM alarm, were identified approximately 80% of the time at both the aforementioned speeds. Conclusion: Using the modified energy-weighted algorithm, several characteristics of the energy weighted spectra could be observed when the used sources were in motion and when the geometric efficiency was low. In particular, the discrimination between 60Co and 40K, which triggers false alarms at the primary inspection sites, can be improved using the proposed algorithm.

본 연구는 재난문자방송 서비스에 영향을 끼치는 요인을 규명하는 것을 연구의 목적으로 하고 있으며, 이를 위하여 요인분석을 통한 서비스 항목과 요인 간의 적절성 검증, 다중회귀분석을 통한 모형 도출 및 영향요인을 도출하였다. 분석결과를 요약하면 다음과 같다. 첫째, 재난문자방송 서비스에 가장 중요 한 영향을 끼치는 서비스 요인은 신속한 전달로 나타났으며, 표준화 계수는 0.179로 분석되었다. 이는 다른 서비스 요인에 비해 월등히 높게 나타나 재난발생 시 재난문자를 신속하게 보낼 수 있도록 시스템 의 개편 및 송출과정에서의 문제가 발생되지 않도록 노력해야 한다. 둘째, 서비스 요인 중 2순위로는 송출기준으로 나타났으며, 이의 표준화 계수는 0.084로 나타났다. 셋째, 서비스 요인 중 3순위로는 이해 하기 쉬운 내용 및 시스템 품질로써 표준화 계수는 0.083으로 나타났다. 이상의 결과를 종합하면, 재난 문자방송에서 가장 중요한 부분은 신속한 전달로, 재난문자방송 시 신속한 전달 측면에 지속적이고 집중적인 노력이 필요하다고 할 수 있다.

This study aimed to identify factors that affect a cell broadcasting system (CBS) service. To this end, this study verified the relevance between service items and factors through factor analysis, and it derived a model through multiple regression analysis and identified the influencing factors. The analysis results can be summarized as follows. First, the service factor with the most significant effect on CBS service was prompt transmission, and its standardized coefficient was 0.179. This coefficient was much higher than that for other service factors, indicating that efforts must be made to prevent problems in system reform and transmission so that emergency alert messages can be sent promptly in case of disasters. Second, transmission standard was the second priority among service factors, and its standardized coefficient was 0.084. Third, comprehensible content and system quality were factors with third priority, and their standardized coefficient was 0.083. In conclusion, as prompt transmission was the most important factor of CBS, constant and intensive efforts must be made to facilitate prompt transmission in the CBS.