• Journal of Drive and Control
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• v.16 no.2
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• pp.59-65
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• 2019

Hydraulic systems have severe nonlinearity inherently compared to other systems like electric control systems. Hence, precise modeling and analysis of the hydraulic control systems are not easy. In this study, the control performance of a hydraulic control system with a feedback linearization compensator and a disturbance observer was analyzed through experiments and numerical simulations. This study mainly focuses on the quantitative investigation of sensitivity on system uncertainties in the hydraulic control system. First, the sensitivity on the system uncertainty of the hydraulic control system with a Feedback Linearization - State Feedback Controller (FL-SFC) was quantitatively analyzed. In addition, the efficacy of a disturbance observer coupled with the FL-SFC for the hydraulic control system was verified in terms of overcoming the control performances deterioration owing to system uncertainty.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.36.2-36.2
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• 2019

Using VLT/MUSE and ALMA data, we present a spatially-resolved analysis of the central part of NGC 5728. We find enhanced star formation (${\sim}1.8M{\odot}/yr/kpc2$) at a region where AGN gas outflows intersect the star formation ring. In contrast, significantly weaker CO emission (~3.5 times) is found at the same region compared to other regions in ring, suggesting positive AGN feedback on star formation. On the other hand, we detect gas outflows outside of the spiral arms, implying that the inflowing gas in the arms is removed (i.e., negative feedback). Even though the positive and negative feedback are expected at the central part of NGC 5728, the impact of the AGN feedback in galaxy scale may be insignificant.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.659-665
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• 2001

Relevance feedback is the most popular query reformulation strategy in a relevance feedback cycle, the user is presented with a list of the retrieved documents and, after examining them, marks those which are relevant. In practice, only the top 10(or 20) ranked documents need to be examined. The main idea consists of selecting important terms, or expressions, attached to the documents that have been identified as relevant by the user, and of enhancing the importance of these terms in a new query formulation. The expected effect is that the new query will be moved towards the relevant documents and away from the non-relevant ones. Local analysis techniques are interesting because they take advantage of the local context provided with the query. In this regard, they seem more appropriate than global analysis techniques. In a local strategy, the documents retrieved for a given query q are examined at query time to determine terms for query expansion. This is similar to a relevance feedback cycle but might be done without assistance from the user.

• Journal of Drive and Control
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• v.16 no.4
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• pp.56-64
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• 2019

Recently, as the environmental regulation for earth moving equipment has been tightened, advanced systems using electronic control have been introduced for energy savings. An IMV(Independent Metering Valve), which consists of four 2-way valves, is one of the electro-hydraulic control systems that provides more flexible controllability and potential for energy savings in excavators, when compared to the conventional 4-way spool valve system. To fully realize an IMV, a two-stage bi-directional flow control valve which can regulate the large amount of flow in both directions, should be developed in advance. A simple design that allows proportional flow control to apply the pilot pressure from the current-controlled solenoid to the spring loaded flow control spool and thus valve displacement, is proportional to the solenoid current. However, this open-loop type valve is vulnerable to flow force which directly affects the valve displacement. Force feedback servo of which the position loop is closed by the feedback spring which interconnects the solenoid valve and flow control spool, could compensate for the flow force. In this study, linearity for the solenoid current input and robustness against load pressure disturbance is investigated by linear analysis of the static nonlinear equations for the IMV proportional flow control valve with feedback spring. Gains of the linear system confirm the performance improvement with the feedback spring design.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.1
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• pp.9-14
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• 2002

Boolean retrieval is simple and elegant. However, since there is no provision for term weighting, no ranking of the answer set is generated. As a result, the size of the output might be too large or too small. Relevance feedback is the most popular query reformulation strategy. in a relevance feedback cycle, the user is presented with a list of the retrieved documents and, after examining them, marks those which are relevant. In practice, only the top 10(or 20) ranked documents need to be examined. The main idea consists of selecting important terms, or expressions, attached to the documents that have been identified as relevant by the user, and of enhancing the importance of these terms in a new query formulation. The expected effect is that the new query will be moved towards the relevant documents and away from the non-relevant ones. Local analysis techniques are interesting because they take advantage of the local context provided with the query. In this regard, they seem more appropriate than global analysis techniques. In a local strategy, the documents retrieved for a given query q are examined at query time to determine terms for query expansion. This is similar to a relevance feedback cycle but might be done without assistance from the user.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.6
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• pp.745-751
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• 2004

In conventional boolean retrieval systems, document ranking is not supported and similarity coefficients cannot be computed between queries and documents. The MMM(Max and Min Model), Paice and P-norm models have been proposed in the past to support the ranking facility for boolean retrieval systems. They have common properties of interpreting boolean operators softly In this paper we propose a new soft evaluation method for web Information retrieval using local context analysis feedback model. We also show through performance comparison that local contort analysis feedback is more efficient and effective than MMM, Paice and P-norm.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.6
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• pp.1022-1038
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• 2017

Wearable smart products contributed to expand the concept of modern clothing in terms of closer communication between wearers and the surrounding environment. This study investigated the concept of wearable smart actuators and characteristics of actuating feedback. The representative product development trends over the past 10 years are examined based on the method of actuating feedback. A first keyword search from Naver and Google reused to select the final 58 products based on the second key keyword actuating feedback. The wearable smart actuator system works in a similar way to a human body system such as those of the information processing process. Actuating feedback is delivered directly to the user as the last signal of the system, which has visual, auditory and tactile feedback. It works in complex at the device to be delivered to the user. Actuator feedback is divided into three types of active and passive, depending on the user situation, the overall purpose of the product, the collected information, and the device dependency. Active actuating feedback determines and actuates the situation on behalf of the user when the user is in an emergency or a disability situation. Passive actuating feedback plays a role in environmental monitoring to help in a healthy daily life.

• International Journal of Computer Science & Network Security
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• v.22 no.10
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• pp.43-50
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• 2022

The students' feedback is important to measure and improve teaching performance. Many teacher performance evaluation systems are based on responses to closed question, but the free text answers can contain useful information which had to be explored. In this paper we present a lexicon-based sentiment analysis to explore students' text feedback. The data was collected from a system for the evaluation of teachers by students developed and used in our university. The students comments are in Romanian language so we built a Romanian sentiment word lexicon. We used this to categorize the feeback text as positive, negative or neutral. In addition, we added a new polarity - indifferent - in order to categorize blank and "I don't answer" responses.

• Journal of Applied Reliability
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• v.10 no.2
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• pp.93-105
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• 2010

The following thesis provides an explanation for the definition of the MIL-HDBK-2155 : Failure Reporting, Analysis and Corrective Action System (FRACAS), which systemizes the collection and analysis of failure data and the feedback process of the results. It also presents a plan based on MIL-HDBK-2155 for the collection and analysis of operating specifications on weapon systems. The collection and analysis of failure data and the feedback process utilizing FRACAS contributes to identifying improvement requirements during equipment operation as well as finding and eliminating the root cause of the failures. The objective of applying FRACAS to weapon systems is to receive source data feedback for reliability enhancements and performance improvements during operation. This is done by recognizing weaknesses in the design or operation by identifying the type of failures that might occur, and by performing Failure Modes, Effects and Criticality Analysis(FMECA) and Failure Tree Analysis(FTA).

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1906-1908
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• 2004

We propose a result on the stabilization of nonlinear time-delay systems via the feedback linearization method. Using the predictor based control and the parametric coordinate transformation, we introduce a stabilizing controller to compensate time delay. Specifically, we present the delay-dependent stability analysis to makes the considered system stable. Also, an illustrative example is provided