• 대한전자공학회논문지
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• 제22권5호
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• pp.69-74
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• 1985

본 논문에서는 먼저 Sensitivity가 가장 낮은 LC Ladder 필터로 부터 FDNR frequency dependent negative resists.) 방식을 이용하여 5차 Butterworth 저역 통과 능동 RC필터를 설계하였으며 능동 RC 필터를 SCF(switched capacito, filter)로 변조하는 과정에서 Bilinear Z변환을 이용하였다. Bilinear Z 변환으로 설계된 SCF에서 aliasing 현상은 피할수 있으나 주파수 대곡이 발생한다. 아나로그 필터를 디지틀 릴터로 변환하면 이러한 영향으로 속단 주파수 영역이 일치하지 않으므로 이것을 적게 하기 위하여 Prewarping을 해준다. 그 결과 Prewarping된 SCF는 Bilinear Z 변환된 SCF보다 각파수 이유이 현저하게 개선됨을 확인하였다.

• International Journal of Control, Automation, and Systems
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• 제4권6호
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• pp.689-696
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• 2006

This paper presents a new algorithm for the closed-loop $H_{\infty}$ composite control of weakly coupled bilinear systems with time-varying parameter uncertainties and exogenous disturbance using the successive Galerkin approximation(SGA). By using weak coupling theory, the robust $H_{\infty}$ control can be obtained from two reduced-order robust $H_{\infty}$ control problems in parallel. The $H_{\infty}$ control theory guarantees robust closed-loop performance but the resulting problem is difficult to solve for uncertain bilinear systems. In order to overcome the difficulties inherent in the $H_{\infty}$ control problem, two $H_{\infty}$ control laws are constructed in terms of the approximated solution to two independent Hamilton-Jacobi-Isaac equations using the SGA method. One of the purposes of this paper is to design a closed-loop parallel robust $H_{\infty}$ control law for the weakly coupled bilinear systems with parameter uncertainties using the SGA method. The other is to reduce the computational complexity when the SGA method is applied to the high order systems.

• 한국지진공학회논문집
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• 제21권2호
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• pp.95-103
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• 2017

In order to modeling seismic isolation system such as lead-rubber bearing (LRB), bilinear model is widely used by many researchers. In general, an actual force-displacement relationship for LRB has a smooth hysteretic shape. So, Bouc-Wen model with smooth hysteretic shape represents more accurately actual hysteretic shape than bilinear model. In this study, seismic responses for seismically isolated nuclear power plant (NPP) with LRB modelled by Bouc-Wen and bilinear models are compared with those of NPP without seismic isolation system. To evaluate effect of earthquake characteristics for seismic responses of NPP isolated by LRB, 5 different site class earthquakes distinguished by Geomatrix 3rd Letter Site Classification and artificially generated earthquakes corresponding to standard design spectrum by Reg. Guide 1.60 are used as input earthquakes. From the seismic response results of seismically isolated NPP, it can be observed that maximum displacements of seismic isolation modelled by Bouc-Wen model are larger than those by bilinear model. Seismic responses of NPP with LRB is significantly reduced than those without LRB. This reduction effect for seismic responses of NPP subjected to Site A (rock) earthquakes is larger than that to Site E (soft soil) earthquakes.

• Journal of applied mathematics & informatics
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• 제31권3_4호
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• pp.425-441
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• 2013

In literature, several strong designated verifier signature (SDVS) schemes have been devised using elliptic curve bilinear pairing and map-topoint (MTP) hash function. The bilinear pairing requires a super-singular elliptic curve group having large number of elements and the relative computation cost of it is approximately two to three times higher than that of elliptic curve point multiplication, which indicates that bilinear pairing is an expensive operation. Moreover, the MTP function, which maps a user identity into an elliptic curve point, is more expensive than an elliptic curve scalar point multiplication. Hence, the SDVS schemes from bilinear pairing and MTP hash function are not efficient in real environments. Thus, a cost-efficient SDVS scheme using elliptic curve cryptography with pairingfree operation is proposed in this paper that instead of MTP hash function uses a general cryptographic hash function. The security analysis shows that our scheme is secure in the random oracle model with the hardness assumption of CDH problem. In addition, the formal security validation of the proposed scheme is done using AVISPA tool (Automated Validation of Internet Security Protocols and Applications) that demonstrated that our scheme is unforgeable against passive and active attacks. Our scheme also satisfies the different properties of an SDVS scheme including strongness, source hiding, non-transferability and unforgeability. The comparison of our scheme with others are given, which shows that it outperforms in terms of security, computation cost and bandwidth requirement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4987-5014
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• 2015

The bilinear pairing, also known as Weil pairing or Tate pairing, is widely used in cryptography and its properties help to construct cryptographic schemes for different applications in which the security of the transmitted data is a major concern. In remote login authentication schemes, there are two major requirements: i) proving the identity of a user and the server for legitimacy without exposing their private keys and ii) freedom for a user to choose and change his password (private key) efficiently. Most of the existing methods based on the bilinear property have some security breaches due to the lack of features and the design issues. In this paper, we develop a new scheme using the bilinear property of an elliptic point and the biometric characteristics. Our method provides many features along with three major goals. a) Checking the correctness of the password before sending the authentication message, which prevents the wastage of communication cost; b) Efficient password change phase in which the user is asked to give a new password after checking the correctness of the current password without involving the server; c) User anonymity - enforcing the suitability of our scheme for applications in which a user does not want to disclose his identity. We use BAN logic to ensure the mutual authentication and session key agreement properties. The paper provides informal security analysis to illustrate that our scheme resists all the security attacks. Furthermore, we use the AVISPA tool for formal security verification of our scheme.

• 대한공간정보학회지
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• 제16권3호
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• pp.105-110
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• 2008

하천의 수리/수문 모델링에 활용하는 하천 지형자료는 하천정비기본계획을 위한 횡단측량을 통하여 취득된 하천단면 자료를 활용하고 있으나 취득되는 단면간의 거리가 다소 커 모델링 과정 중 보다 조밀한 간격의 단면형상을 필요로 하는 경우에도 단면자료를 취득할 수 없을 뿐만 아니라 관측점간의 직선거리를 고려하는 보간기법들의 특성에 의하여 현실적인 하천의 형상을 반영하지 못하는 문제점이 있다. 본 연구에서는 대표적인 수체부 하천 지형자료라 할 수 있는 하천정비기본계획상의 하천단면자료를 이용하여 하천의 형상을 효율적으로 추정하고자 하였으며 관측된 하천단면자료들 사이의 임의 단면을 생성하는 알고리즘을 제시함으로써 GIS 자료를 이용한 수리/수문 모델링에서 쉽게 활용이 가능하도록 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.386-389
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• 1991

The problem of constructing an bilinear 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 an unknown inputs. The bilinear observer theory for system with unknown inputs is exploited and applied to the problem.

• Communications for Statistical Applications and Methods
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• 제17권5호
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• pp.639-645
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• 2010

We consider a subdiagonal bilinear model and give sufficient conditions for the associated Markov chain defined by Pham (1985) to be uniformly ergodic and then obtain the $\beta$-mixing property for the given process. To derive the desired properties, we employ the results of generalized random coefficient autoregressive models generated by a matrix-valued polynomial function and vector-valued polynomial function.

• ETRI Journal
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• 제34권5호
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• pp.783-786
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• 2012

This letter proposes a more advanced joint maximum a posteriori (MAP) adaptation using a prior model based on a probabilistic scheme utilizing the bilinear transformation (BIT) concept. The proposed method not only has scalable parameters but is also based on a single prior distribution without the heuristic parameters of the previous joint BIT-MAP method. Experiment results, irrespective of the amount of adaptation data, show that the proposed method leads to a consistent improvement over the previous method.

• 대한수학회보
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• 제47권5호
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• pp.889-905
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• 2010

In this paper, a distribution free approach to the parameter estimation of a simple bilinear model with periodic coefficients is presented. The proposed method relies on minimum distance estimator based on the autocovariances of the squared process. Consistency and asymptotic normality of the estimator, as well as hypotheses testing, are derived. Numerical experiments on simulated data sets are presented to highlight the theoretical results.