• Journal of the Korean Institute of Intelligent Systems
• /
• v.11 no.7
• /
• pp.628-632
• /
• 2001

We propose time-frequency (TF) tools for analyzing linear time-varying (LTV) systems and nonstationary random processes. Obtained warping the narrowband Weyl symbol (WS) and spreading function (SF), the new TF tools are useful for analyzing LTV systems and random processes characterized by generalized frequency shifts, This new Weyl symbol (WS) is useful in wideband signal analysis. We also propose WS an tools for analyzing systems which produce dispersive frequency shifts on the signal. We obtain these generalized, frequency-shift covariant WS by warping conventional, narrowband WS. Using the new, generalized WS, we provide a formulation for the Weyl correspondence for linear systems with instantaneous of linear signal transformation as weighted superpositions of non-linear frequency shifts on the signal. Application examples in signal and detection demonstrate the advantages of our new results.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.267-269
• /
• 2005

This paper describes a consideration on the sampling in linearly time-varying (LTV) systems in view of the convenience in digital signal processing. The relation between a continuous-time and a discrete-time system models is investigated for a simple linear time-invariant system. Based on the results of the investigation, we first consider discrete-time models for LTV systems, Then the simplicity of the models in terms of microprocessor-based digital signal processing is compared.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2003.05a
• /
• pp.280-284
• /
• 2003

효과적인 CRM(고객관계관리)을 위해서 고객의 가치를 파악하는 것은 매우 중요하다. 모든 고객이 같은 가치를 제공하지 않기 때문에 차별적인 서비스를 통해 장기적인 관점에서 기업의 수익을 최대화한다는 것이 CRM의 기본전제가 되기 때문이다. 기존의 고객가치를 측정하는 것은 LTV(고객생애가치)를 중심으로 연구되어 왔다. 그러나 이러한 LTV는 환경의 변동성, 고객의 변동성 등 많은 불확실성을 안고 측정될 수밖에 없고 단순히 과거 기업에게 제공된 과거 수익의 추이를 고려하기 때문에 실제 세분화 시 간과하게 되는 점이 많다. 따라서 본 논문에서는 단기적인 활용관점에서 고객의 이탈률(Churn Rate)을 고려하여 고객의 가치를 현재가치, 잠재가치로 나누어 측정하고 이를 통해 고객 세분화의 방안을 제시해 본다.

• Structural Monitoring and Maintenance
• /
• v.4 no.4
• /
• pp.365-379
• /
• 2017

This paper presents a comparison of the black-box and the physics based derived gray-box models for subspace identification for structures subjected to support-excitation. The study compares the damage detection capabilities of both these methods for linear time invariant (LTI) systems as well as linear time-varying (LTV) systems by extending the gray-box model for time-varying systems using short-time windows. The numerically simulated IASC-ASCE Phase-I benchmark building has been used to compare the two methods for different damage scenarios. The efficacy of the two methods for the identification of stiffness parameters has been studied in the presence of different levels of sensor noise to simulate on-field conditions. The proposed extension of the gray-box model for LTV systems has been shown to outperform the black-box model in capturing the variation in stiffness parameters for the benchmark building.

• Proceedings of the Safety Management and Science Conference
• /
• 2002.05a
• /
• pp.115-120
• /
• 2002

Today's environment of enterprise is changing. They have to face customer' demands with the right product, the right service and supply them at the right time. And also cut down logistics and inventory cost and bring up the profit as much as they can. This means the change of putting enterprise first in importance to putting customer first importance. therefore to correspond to customer's demand, shorting lead time is becoming a essential condition. The answer to this changes of environment is supply chain management. In this paper, It consolidates the necessity on a LTV(Life Time Value) and analyzes data which is concerned of Customer Value. Under the these environments, defines the LTV(Life Time Value) rule that can improve the customer value.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1015-1022
• /
• 2009

Currently, Korean real estate market has experienced cooling down of the business because of the global economic crisis which resulted from the subprime mortgage lending practice. In response, the Korean government has enforced various policies at the base of deregulating real estate speculation, such as increasing Loan to value ratio (LTV) in order to stimulate housing demand and supply. However, these policies seemed to result in deep confusion in the Korean housing market. Furthermore, analysis for housing market forecasting, especially international financial crisis on Korean real estate market, has been partial and fragmentary, therefore comprehensive solution and systematical approach is required to analyze the real estate and real estate financial market including causal nexus between market determining factors. In an integrated point of view, applying the system dynamics modeling, the paper aims at proposing Korean Real Estate and Mortgage market dynamics models based on fundamental principles of housing market determined by supply and demand. We also find the impact of deregulation policies focusing on mortgage loan which is the main factors of policies.

• 주택과사람들
• /
• s.222
• /
• pp.52-55
• /
• 2008

지난 10월 21일, 정부가 올 들어 다섯 번째 부동산 대책을 발표했다. 건설 부문 유동성 지원과 금융 규제 완화 등이 주요 골자다. 이번에 발표된 금융 규제 완화책이 주택 거래를 정상화시킬 방안이 될 수 있을지 논란이 되고 있다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.5
• /
• pp.468-476
• /
• 2019

This paper presents the means of improving the strength of LTV's FRP structure for resolve and prevent quality problems. LTV secures enough kerb weight by applying FRP materials at hood and rear van assembly. However, because of FRP's inherent limitations, many initial quality problems such as crack at connections have occurred. Moreover, hood assy' is concerned about fall of endurance, because hood assy' have operated in abnormal condition. Therefore, this study executes lamination structure optimizations of FRP structure for improving bending strength. As a results, hood and rear van's bending strength at connections is improved 8.1 times and 1.5 times, respectively. Also hood assy's plate secures endurance life and improve 1.7 times of critical load about abnormal operating conditions through 1.4 times improvement of bending strength.

• Proceedings of the Korea Database Society Conference
• /
• 2001.06a
• /
• pp.33-41
• /
• 2001

WHY : 고객으로 부터의 장기적인 수익성을 확보하면서 동시에 고객을 만족시키기 위하여 (LTV와 CS를 동시에 고려) WHO : 전사적으로 - 특정부서에 국한되지 않음 - 영업, 카드관리, 물류, 서비스, 신용 관리 등 전체 고객 관련업무(Cross-Functional) - 기획 및 경영층의 직접 참여 (중략)

• Journal of Microbiology and Biotechnology
• /
• v.28 no.2
• /
• pp.246-254
• /
• 2018

Enzyme fermentation is a type of food processing technique generally used to improve the biological activities of food and herbal medicines. In this study, a Syzygii Flos (clove) extract was fermented using laccase derived from Trametes versicolor (LTV). The fermented clove extract showed greater neuroprotective effects against glutamate toxicity on HT22 than the non-fermented extract did. HPLC analysis revealed that the eugenol (1) and dehydrodieugenol (2) contents had decreased and increased, respectively, after fermentation. The content of 2 peaked at 1 h after fermentation to $103.50{\pm}8.20mg/g_{ex}$ (not detected at zero time), while that of 1 decreased to $79.54{\pm}4.77mg/g_{ex}$ ($185.41{\pm}10.16mg/g_{ex}$ at zero time). Compound 2 demonstrated promising HT22 neuroprotective properties with inhibition of $Ca^{2+}$ influx, the overproduction of intracellular reactive oxygen species, and lipid peroxidation. In addition, LTV showed the best fermentation efficacy compared with laccases derived from Pleurotus ostreatus and Rhus vernicifera.