• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.101-106
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• 1990

The problem of constructing an observer for use in the control of superheater temperature with desuperheater is considered. The distributed heat input into the superheater is usually not available for use in the observer, and hence is treated as a disturbance. The observer theory for systems with unknown inputs is exploited and applied to the problem. Approximation of the heat input utilizing the specific heat input distribution pattern is also considered.

• 전자공학회논문지SC
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• 제40권3호
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• pp.117-126
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• 2003

본 연구에서는 월쉬함수를 이용하여 샘플링 구간내에서 데이터를 처리할 수 있는 온라인 월쉬변환과 샘플링 구간내에서 미분 방정식을 계산할 수 있는 새로운 온라인 월쉬함수 미분연산법을 제안하였다. 스케일링 인자의 도입과 다음구간에서의 초기조건을 계산하여 줌으로써 임의의 샘플링 시간을 취할 수 있게 하였으며 제안된 월쉬함수 온라인 알고리즘을 이용하여 기존의 직교함수가 가지는 최종시간까지의 신호를 모두 알고 있어야 그 적용이 가능하다는 단점을 제거하였다. 유사변환법을 이용하여 유도된 동적 시스템에 대한 Luenberger관측기를 월쉬함수를 이용하여 새롭게 변환함으로써 관측기에 포함된 출력의 미분항을 없애기 위한 불필요한 관측기 방정식의 분할을 피하였으며 대수적으로 상태 및 미지입력을 추정하였다. 제안된 방법을 이용하면 실시간 처리를 요하는 시스템에 유용하게 적용될 것으로 기대된다.

• 전자공학회논문지SC
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• 제47권2호
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• pp.16-24
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• 2010

본 논문은 불특정한 외란을 가진 비선형 시스템에서의 백스태핑 기법을 이용한 새로운 퍼지 외란 관측가 설계 방법을 제안한다. 먼저, 퍼지 논리 시스템을 이용하여 불특정한 외란을 관측하기 위한 관측 입력을 가진 퍼지 외란 관측기를 설계한다. 제안된 외란 관측기가 불특정한 외란을 관측하는 것을 증명하기 위해 와란 관측 오차 시스템을 도입한다. 백스태핑 기법을 도입하여 각 단계에서의 퍼지 외란 관측기의 파라마터 적응 규칙과 외란 관측기의 관측 입력을 유도하고 외란 오차 시스템의 안정성을 증명한다. 제안된 외란 관측기의 명확성을 증명하기 위해서 모의 실험 예제들을 제공한다.

• 스마트미디어저널
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• 제13권8호
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• pp.16-25
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• 2024

Recently, there has been a growing emphasis on identifying both known and unknown diseases in plant disease recognition. In this task, a model trained only on images of known classes is required to classify an input image into either one of the known classes or into an unknown class. Consequently, the capability to recognize unknown diseases is critical for model deployment. To enhance this capability, we are considering three factors. Firstly, we propose a new logits-based scoring function for unknown scores. Secondly, initial experiments indicate that a compact feature space is crucial for the effectiveness of logits-based methods, leading us to employ the AM-Softmax loss instead of Cross-entropy loss during training. Thirdly, drawing inspiration from the efficacy of transfer learning, we utilize a large plant-relevant dataset, PlantCLEF2022, for pre-training a model. The experimental results suggest that our method outperforms current algorithms. Specifically, our method achieved a performance of 97.90 CSA, 91.77 AUROC, and 90.63 OSCR with the ResNet50 model and a performance of 98.28 CSA, 92.05 AUROC, and 91.12 OSCR with the ConvNext base model. We believe that our study will contribute to the community.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1278-1282
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• 2003

A new interacting multiple model (IMM) method using intelligent input estimation (IIE) is proposed to track a maneuvering target. In the proposed method, the acceleration level for each sub-model is determined by IIE-the estimation of the unknown acceleration input by a fuzzy system using the relation between maneuvering filter residual and non-maneuvering one. The genetic algorithm (GA) is utilized to optimize a fuzzy system for a sub-model within a fixed range of acceleration input. Then, multiple models are composed of these fuzzy systems, which are optimized for different ranges of acceleration input. In computer simulation for an incoming ballistic missile, the tracking performance of the proposed method is compared with those of the input estimation (IE) technique and the adaptive interacting multiple model (AIMM) method.

• 전자공학회논문지B
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• 제33B권5호
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• pp.73-82
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• 1996

In this paper, an efficient algorithm for recognizing and positioning occuluded objects in a two-dimensional plane is presented. Model objects and unknown input image are approximated by polygonal boundaries, which are compactly represented by shape functions of the polygons. The input image is partitioned into measningful segments whose end points are at the locations of possible occlusion - i.e. at concave vertices. Each segment is matched against known model objects by calculating a matching measure, which is defined as the minimum euclidean distance between the shape functions. An O(mm(n+m) algorithm for computing the measure is presentd, where n and m are the number of veritces for a model and an unknown object, respectively. Match results from aprtial segments are combined based on mutual compatibility, then are verified using distance transformation and translation vector to produce the final recognition. The proposed algorithm is invariant under translation and rotation of objects, which has been shown by experimental results.

• 한국정밀공학회지
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• 제13권7호
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• pp.133-139
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• 1996

전형적인 상태 관측기에서는, 외란이 시스템 입력에 가해지는 경우 시스템의 상태 추정이 불가능하다. 이러한 상태관측 문제에 대한 한가지 대책법으로서 비례적분(PI) 관측기가 제안되어 스텝외란의 소거에 대한 유효성이 밝혀져 로바스트 제어기 설계에 대한 응용으로서 널리 연구가 행해져 왔다. 그러나, 미지입력에 대한 PE 관측기 설계는 여전히 문제로 남아 있다. 이 논문에서는 미지입력 PI 관측기의 설계법을 제안하고, 이에 대한 응용으로서 완전 LTR을 실현할 수 있는 결과를 보인다. 먼저, 입력의 정보없이 시스템의 상태를 추정할 수 있는 미지입력 PI 관측기의 충분조건을 제안하고, PE 관측기의 설계에 요구되는 필요충분조건을 보인다. 이러한 조건은 완전 LTR의 실현을 위한 직접적인 요구조건임을 보인다. 따라서, 완전 LTR을 달성하면서 지정한 관측기의 극을 지니는 PI 관측기 설계가 가능하다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.665-667
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• 1999

An adaptive algorithm is presented for diagnosis of actuator faults. The concept of unknown input decoupling is combined with an adaptive observer, leading to an adaptive diagnostic observer, which has the robustness property in the presence of an unmeasurable term such as uncertainties. The observation error equation for the adaptive diagnostic observer does not depend on the effect of uncertainties and used to construct an adaptive diagnostic algorithm that provides the estimates of the gains of actuators, which can be obtained directly via the use of the augmented error technique. The simulation results indicate that the proposed algorithm is more realistic in the sense that better robustness properties can be assured without knowledge about uncertainties and is potentially useful in the development of a fault tolerant control system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2182-2184
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• 2004

This paper presents a systematic and straightforward fault estimation approach for process fault detection. isolation and accommodation. The approach includes the design of a reduced-order observer and an algebraic-fault estimator. The observer is designed for an unknown input and fault-free system, which is obtained by coordinate transformations of original systems with unknown inputs and faults. The observer information is devoted to- the fault estimation for fault detection and isolation. The fault estimates can be used to form an additional control input to accommodate the fault. The suggested scheme is verified through simulation studies performed on the control of a vertical takeoff and landing (VTOL) aircraft in the vertical plane.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.93.5-93
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• 2001

In chaos control proposed until today, the target system is known in many cases. However, since the generating mechanism of chaos is not strange in few case, it is required to control only by the time series data observed from the system. Then, as the method of stabilizing the state of the unknown system, we propose the technique made combining PFC and DFC using a parameter which indicates the balance of both methods. The prediction values at the PFC input portion are determined from the known output using RNN. The input is impressed only near UPO calculated from the output using the concept of UPR.