• 한국항공운항학회지
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• 제23권2호
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• pp.63-68
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• 2015

This paper presents the algorithm for envelope protection of helicopters. The algorithm consists of two feedback control loops: inner loop and outer loop. As an inner loop control, model following control is designed to meet the ADS-33 handling qualities specification by minimizing the tracking errors between the responses of the actual model and those of the command filter. In order to implement envelope protection, saturation limiter is imposed to command channels in command filter, whose limits are computed corresponding to the envelope limit. Fast model predictive control is designed as an outer loop control to deal with saturation constraints generated by the inner loop envelope protection and also imposed by outer loop envelope protection variables. Simulation results show that the proposed algorithm yields good envelope protection performance.

• 한국해양공학회지
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• 제30권2호
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• pp.134-140
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• 2016

An envelope protection system is a control system that allows a submarine to operate freely using its own operational envelope without exceeding the structural limit, dynamic limit, and control input limit. In this paper, an envelope protection system for the pitch angle of a submarine is designed using a dynamic trim algorithm. A linear quadratic regulator and artificial neural network are used for the true dynamics approximation. A submarine maneuvering simulation program developed using experimental data is used to validate the designed envelope protection system. Simulation results show the effectiveness of the designed envelope protection system.

• International Journal of Aeronautical and Space Sciences
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• 제12권3호
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• pp.241-251
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• 2011

Most large commercial aircrafts and high performance military aircrafts use fly-by-wire (FBW) or fly-by-light systems to improve their controllability, comfort, and safety. A flight envelope protection technique is used with flight control systems utilizing the FBW technique. Such flight envelope protection systems prevent these aircraft from exceeding the structural/aerodynamic limits and control their surface limits. This is accomplished by predicting the values of the future state variables and adaptively compensating the control action. In this study, the conventional dynamic trim algorithm of the flight envelope protection is modified to increase the method accuracy and to handle cases with multiple variables. Numerical simulation is also performed to verify the performance of the proposed method.

• International Journal of Aerospace System Engineering
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• 제2권2호
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• pp.73-78
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• 2015

According to the characteristic of carrier-based aircraft, the method of solving safe set during arresting landing is discussed in this paper based on optimal control and invariant set theory. The safe sets of carrier aircraft are evaluated in different states on the characteristic of longitudinal augmented system by using the level set method. Then, the influence on the boundary of safe set under various factors is analyzed. At last, the maneuverability envelope protection is established based on the corresponding theory, and the validity of the system is verified through simulation. The results demonstrate preliminarily that: compared with mass and thrust, the elevator is the greatest influence factor for the boundary of safe set; the dynamic trajectory of carrier-based aircraft can be located at the interior of safe set effectively with the maneuverability envelope protection.

• 한국항공우주학회지
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• 제38권4호
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• pp.327-334
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• 2010

최근 개발된 항공기는 대부분 디지털 Fly-By-Wire(FBW) 혹은 광신호를 사용하는 Fly-By-Light(FBL) 시스템을 사용하고 있다. 이러한 시스템들은 조종사의 직접 조종으로는 불가능하거나 어려운 복잡한 임무의 수행, 비행범위 확장, 신뢰성 향상 등의 장점을 가지고 있다. FBW 기술을 적용한 비행제어기술이 발전됨에 따라 운항 시 안정성 확보 및 보다 효율적인 임무수행을 위해 비행영역(Flight Envelope) 보호의 개념이 항공기 설계에 있어 중요한 문제로 부각되고 있다. 본 논문에서는 dynamic trim 알고리즘, peak response estimation, 제어이득 스케쥴링 등의 방법을 이용해서 항공기의 비행영역 보호를 수행하고, 각 방법의 성능을 비교하여 최적의 제어기를 설계하는 연구를 수행하였다.

• ETRI Journal
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• 제25권1호
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• pp.52-54
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• 2003

We propose an improved algorithm for detecting audio watermarks based on a spread spectrum in the spectral domain. Since the energy of a watermark is much smaller than that of the cover audio data, pre-processing to reduce the effect of the cover data is needed to reliably extract watermarks. We introduce a spectral envelope filter as a pre-process that enhances detecting performance by filtering out the intrinsic spectral character of cover data. The proposed watermarking structure can be easily included in the compression system and can extract watermarks from partially decompressed spectral data. Our experimental results demonstrate that with a bit error rate of around 10 dB against general attacks, the proposed detecting scheme works better than detectors without the spectral filter.

• KIEAE Journal
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• 제14권4호
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• pp.61-68
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• 2014

Due to rapid climate changing and the need for energy conservation, environment friendly initiatives have emerged, and regulations to support establishment of green structures in construction have been legislated and enacted. In this study, the supporting of green build method act for rapid climate change and energy conservation. Using green build method, protecting surrounding ecosystem and developing green building continuously, I suggest alternative for protection of the environment. Identifies Envelope Design Elements among various construction Green Building Design Guidelines. Green buildings that we extract the Green Building envelope design from Design Guideline, select the object building through the green buildings examples of public institution relocation projects. Since then analyzes the planned schematic design and Green Envelope Design Elements and Green Building Certification(G-SEED). So, that future directions for planning correlation of Green Building and Design Guidelines about Green Design Elements Can be presented.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2000년도 추계학술발표대회
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• pp.78-82
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• 2000

The AIDS epidemic continues unabated in many part of the world. After near two decades, no vaccine is available to combat the spread of this deadly disease. Much of the HIV -1 vaccine effort during the past decade has focused on the viral envelope glycoprotein, largely because it is the only protein that can elicit neutralizing antibodies (Nabs). Eliciting broadly cross-reactive Nabs has been a primary goal. The intrinsic genetic diversity of the viral envelope, however, has been one of the major impediments in vaccine development. We have recently completed a comprehensive study examining whether it is possible to elicit broadly acting Nabs by immunizing monkeys with mixtures of envelope proteins from multiple HIV -1 isolates. We compared the humoral immune responses elicited by vaccination with either single or multiple envelope proteins and evaluated the importance of humoral and non-humoral immune response in protection against a challenge virus with a homologous or heterologous envelope protein. Our results show that (1) Nab is the correlate of sterilizing immunity, (2) Nabs against primary HIV -1 isolates can be elicited by the live vector-prime/protein boost approach, and (3) polyvalent envelope vaccines elicit broader Nab response than monovalent vaccines. Nonetheless, our findings clearly indicate that the increased breadth of Nab response is by and large limited to strains included in the vaccine mixture and does not extend to heterologous non-vaccine strains. Our study strongly demonstrates how difficult it may be to elicit broadly reactive Nabs using envelope proteins and sadly predicts a similar fate for many of the vaccine candidates currently being evaluated in clinical trials. We have started to evaluate other vaccine candidates (e.g. genetically modified envelope proteins) that might elicit broadly reactive Nabs. We are also exploring other vaccine strategies to elicit potent cytotoxic T lymphocyte responses. Preliminary results from some of these experiments will be discussed.

• 한국해양공학회지
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• 제32권3호
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• pp.208-212
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• 2018

In this paper, we focus on planing avoidance control for a supercavitating underwater vehicle based on the potential function method. The planing margin can be calculated using the relative position between the cavity center and vehicle center at the end of the vehicle. The planing margin was transformed into a limit variable such as the pitch angle and yaw angle limit. To prevent the vehicle attitude from exceeding the limit variable, a potential function based planing envelope protection method was proposed. The planing envelope protection system overrides commands from the tracking controller, and the vehicle attitude converges to a desired angle, in which the potential function is minimized. Numerical simulations were performed to analyze the physical feasibility and performance of the proposed method. The results showed that the proposed methods eliminated the planing, allowing the vehicle to follow tracking commands.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.235-242
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• 2012

In recently constructed building, It has become fashionable again that the heavy external skin system such as a Stone Finished Envelope. There are Squared Steel Pipe Methods, C-Shaped Steel Pipe Methods, and Aluminum Beam Methods in the structure of a heavy external skin system. The Aluminum Beam Methods is often misunderstood as a Plane Truss Structure, but this method is not appropriate to be called to a truss structure but a beam methods. The Aluminum Beam Methods is the most Eco-friendly methods in terms of Quality assurance, Efficiency, Safety, Construction period, Durability, and Recyclability. And this Methods is also very appropriate in considering the point of Energy conservation, Waste reduction, Long-life architecture, Replacement parts, Environmental protection, Public efficiency, and Building demolition.