• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.1-6
• /
• 1993

This report proposes a novel method of identification of continuous time-delay systems from sampled input-output data. By the aid of a digital pre-filter, an approximated discrete-time estimation model is first derived, in which the system parameters remain in their original form and the time delay need not be an integral multiple of th sampling period. Then an identification method combining the common linear least squares(LS) method or the instrumental variable(IV) method with the genetic algorithm(GA) is proposed. That is, the time-delay is selected by the GA, and the system parameters are estimated by the LS or IV method. Furthermore, the proposed method is extended to the case of multi-input multi-output systems where the time-delays in the individual input channels may differ each other. Simulation resutls show that our method yields consistent estimates even in the presence of high measurement noises.

• Transactions of The Korea Fluid Power Systems Society
• /
• 제3권1호
• /
• pp.7-14
• /
• 2006

In this paper, an in-process diagnosis method for performance of position control servo system was studied, which was based upon null bias, slew-rate ratio and delay time measurement. Slew-rate ratio and delay time were analyzed by theoretical analysis, computer simulation and experiment. As a result of these analysis, when spool of servovalve was weared, slew-rate ratio was decreased and delay time was increased.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 한국건축시공학회 2015년도 추계 학술논문 발표대회
• /
• pp.172-173
• /
• 2015

Construction project involves numerous repetitive operations. Especially in high-rise and apartment houses projects, the amount of repetitive operations increase and a preceding operations delay causes serious damage to the total duration of the project. This study deducts work delay factors by site engineer interview and survey. The study analyzes daily report data to deduct crucial processes affecting masonry work which has been investigated to be one of preliminary processes conducted at the beginning of finish work.

• Journal of Genetic Medicine
• /
• 제18권1호
• /
• pp.44-47
• /
• 2021

Cerebral creatine deficiency syndrome (CCDS) is a disorder where a defect is present in transport of creatine in the brain. Creatine plays an essential role in the energy metabolism of the brain. This is a genetic disorder, autosomal recessive or X linked, characterized by intellectual disability, speech and language delay, epilepsy, hypotonia, etc. Until recently very few number of cases have been reported. Here we report a case of 1.5-year-old boy who had epilepsy (epileptic spasm and generalized tonic clonic seizure), intellectual disability, microcephaly, hypotonia and speech delay. His magnetic resonance imaging of brain showed cortical atrophy and electroencephalography showed burst suppression pattern. The diagnosis was confirmed by clinical exome sequencing which showed novel mutation of SLC6A8+ in exon 9, suggestive of X linked recessive CCDS. The patient was then treated with glycine, L-arginine and creatine monohydrate with multiple antiepileptic drugs.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 1996년도 추계학술대회 논문집
• /
• pp.987-993
• /
• 1996

This report suggests a new non-linear friction compensation for digital control systems. This control adopts a hysteric nonlinear clement which can introduce the phase lead of the control system to compensate the phase delay comes from the inherent time delay of a digital control. The Lyapunov direct method is used to prove the asymtotic stability of the suggested control, and the stability and the effectiveness are verified analytically and experimentally on a single axis servo driving system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 한국소음진동공학회 2002년도 추계학술대회논문초록집
• /
• pp.320.1-320
• /
• 2002

In a hard disk drive (HDD) control system, a state-space controller/observer design is popularly adopted fur its advantages such as effective filtering of position and velocity, use of estimation error to handle servo defects, etc. In this report, a systematic method is proposed to accommodate the transport delay in the plant dynamics into the state estimator. (omitted)

• Journal of the Korea Society of Computer and Information
• /
• 제17권5호
• /
• pp.41-48
• /
• 2012

A Vehicular Ad-hoc Network (VANET) is a vehicular specific type of a mobile ad-hoc network, to provide temporary communications among nearby vehicles. Mobile node of VANET consumes energy and resource with participating in the member of network. In a VANET, data replication and cooperative caching have been used as promising solutions to improve system performance. Existing cooperative caching scheme in a VANET mostly focuses on weak consistency is not always satisfactory. In this paper, we propose an efficient cache management scheme to maintain strong data consistency in a VANET. We make an adaptive scheduling scheme to broadcast Invalidation Report (IR) in order to reduce query delay and communication overhead to maintain strong data consistency. The simulation result shows that our proposed method has a strength in terms of query delay and communication overhead.

• Clinical and Experimental Pediatrics
• /
• 제59권2호
• /
• pp.91-95
• /
• 2016

We report the case of a 22-month-old boy with a new mosaic partial unbalanced translocation of 1q and 18q. The patient was referred to our Pediatric Department for developmental delay. He showed mild facial dysmorphism, physical growth retardation, a hearing disability, and had a history of patent ductus arteriosus. White matter abnormality on brain magnetic resonance images was also noted. His initial routine chromosomal analysis revealed a normal 46,XY karyotype. In a microarray-based comparative genomic hybridization (aCGH) analysis, subtle copy number changes in 1q32.1-q44 (copy gain) and 18q21.33-18q23 (copy loss) suggested an unbalanced translocation of t(1;18). Repeated chromosomal analysis revealed a low-level mosaic translocation karyotype of 46,XY,der(18)t(1;18) (q32.1;q21.3)[12]/46,XY[152]. Because his parents had normal karyotypes, his translocation was considered to be de novo. The abnormalities observed in aCGH were confirmed by metaphase fluorescent in situ hybridization. We report this patient as a new karyotype presenting developmental delay, facial dysmorphism, cerebral dysmyelination, and other abnormalities.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
• /
• pp.147-150
• /
• 1998

The report presents basic functions of Time-delay System Toolbox (for MATLAB) -the general-purpose software package for Computer Aided Design of control systems with delays. The Toolbox is a collection of algorithms, expressed mostly in m-files for simulating and analysis of MIMO linear and nonlinear systems with discrete and distributed (time-varying) delays.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권8호
• /
• pp.61-67
• /
• 2020

This paper examines whether the combination of risk management and audit committee functions are associated with audit report lag. Audit report lag is considered an important aspect of the financial reporting. The financial reports are the main source of information for shareholders through which they make their decisions and it assists in reducing the information asymmetry. As the internal control mechanisms substitute the external ones, the internal board committees formed by the board of directors can reduce the audit work and, consequently, reduces the audit report lag. A key committee is the risk management committee. This paper examines whether the combination of risk management and audit committee functions are associated with audit report lag. We posit that a combination of such functions in one committee refereed as audit committee affects the audit report delay. Data were obtained from 198 manufacturing companies listed on the Saudi Stock Exchange (Tadawul) for the years 2016-2018. A pooled OLS regression analysis shows that a combination of risk management and audit committee functions in a stand-alone committee named "audit committee" is associated with longer audit report lag. The outcomes suggest companies should prioritize the establishment of standalone risk management committee with activities separated from those of audit committees.