• Journal of the Korean Mathematical Society
• /
• v.46 no.1
• /
• pp.71-82
• /
• 2009

In this paper, a stage-structured predator-prey system with impulsive perturbations and time delays is presented to investigate the ecological problem of how a pest population and natural enemy population can coexist. Sufficient conditions are obtained using a discrete dynamical system determined by a stroboscopic map, which guarantee that a 'predator-extinction' periodic solution is globally attractive. When the impulsive period is longer than some time threshold or the impulsive harvesting rate is below a control threshold, the system is permanent. Our results provide some reasonable suggestions for pest management.

• Journal of Biosystems Engineering
• /
• v.23 no.4
• /
• pp.381-390
• /
• 1998

An algorithm to extract the 3-D geometric information of a static object was developed using a set of 2-D computer vision system and a laser structured lighting device. As a structured light pattern, multi-parallel lines were used in the study. The proposed algorithm was composed of three stages. The camera calibration, which determined a coordinate transformation between the image plane and the real 3-D world, was performed using known 6 pairs of points at the first stage. Then, utilizing the shifting phenomena of the projected laser beam on an object, the height of the object was computed at the second stage. Finally, using the height information of the 2-D image point, the corresponding 3-D information was computed using results of the camera calibration. For arbitrary geometric objects, the maximum error of the extracted 3-D feature using the proposed algorithm was less than 1~2mm. The results showed that the proposed algorithm was accurate for 3-D geometric feature detection of an object.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.6 s.261
• /
• pp.651-658
• /
• 2007

A new tree-structured neural network classifier is proposed for the automatic real-time inspection of cold-rolled steel strip surface defects. The defects are classified into 3 groups such as area type, disk type, area & line type in the first stage of the tree-structured neural network. The defects are classified in more detail into 11 major defect types which are considered as serious defects in the second stage of neural network. The tree-structured neural network classifier consists of 4 different neural networks and optimum features are selected for each neural network classifier by using SFFS algorithm and correlation test. The developed classifier demonstrates very plausible result which is compatible with commercial products having high world-wide market shares.

• International Journal of Advanced Culture Technology
• /
• v.6 no.4
• /
• pp.262-265
• /
• 2018

Deep learning, a sub-field of machine learning changing the prospects of artificial intelligence (AI) because of its recent advancements and application in various field. Deep learning deals with algorithms inspired by the structure and function of the brain called artificial neural networks. This works reviews basic architecture and recent advancement of deep structured learning. It also describes contemporary applications of deep structured learning and its advantages over the treditional learning in artificial interlligence. This study is useful for the general readers and students who are in the early stage of deep learning studies.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.5
• /
• pp.1212-1218
• /
• 1999

This paper proposes a new multipath interconnection network(MIN) structure for improving performance which uses widely in the design of multiprocessing, ATM system and VOD server. For improving performance such as passthrough ratio and packet latency, it proposes new routing method which routes one of the collided packets into the i+1-th switching stage of the adding Banyan MIN network when it occurred collision at the i-th switching stage of the basic MIN again when they collide each other. The new improved performance MIN network has been compared with MBSF, TBSF and PBSF structured MIN network from the viewpoint of passthrough ratio and the number of switching stage vs. passthrough ratio. It is shown to improve a performance and to be a simple structure which reducing the number of switching stage of adding MIN in comparison with other structured MIN including TBSF.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2008.04a
• /
• pp.435-441
• /
• 2008

Building Information Modelings(BIM) are more complex than typically required for early phase of the design process of a building. Construction projects have many participants from various disciplines involved throughout the entire process. Therefore the success of the project greatly depend on the efficiency of decision-making using the information generated from each process stage. This research utilized an ontology to provide an underlying structure of objects and relationships of a building. The OWL is introduced as a main vehicle to encode the information and knowledge about the building structures and spaces. A case study was conducted to develop a structured representation of an ontology where the relationships among the necessary components in the stage of preliminary design were to be automatically utilized to plan on the sizes of each room in a building and structured thoroughly with a simple structured representation.

• The Journal of Information Systems
• /
• v.15 no.4
• /
• pp.125-147
• /
• 2006

Internet shopping mall has dual nature of information technology features defined by the web-based application system and marketing features explained by the shopping marketplaces. The purpose of this study aims at analyzing the consumer's attempt to purchase and re-purchase intention to the internet shopping mall to combine the IT perspective and the marketing perspective. This paper develop the integrated research model with the acceptance behaviors of customers through consumer's purchase decision process(pre-purchase stage and post-purchase stage). The results from an empirical survey as follows: First, the integrated model is valid in predicting the acceptance of the internet shopping malls by using structured equation modeling. Second, there are the differences between pre-purchase stage and post-purchase stage by each conceptual constructs. Finally, the results of MSEM(Multi-group Structured Equation Modeling) indicate the perceived ease of use and perceived trust to the attitude to the internet shopping mall is more effectively predicted at the pre-purchase stage. Vice versa, the perceived usefulness to the intention to the purchase intention of internet shopping mall is more effectively predicted at the post-purchase stage. This study provides an integrative approach to develop the effective and successful internet shopping mall strategy.

• Kyungpook Mathematical Journal
• /
• v.49 no.4
• /
• pp.605-618
• /
• 2009

A stage-structured predator-prey system with time delay and Beddington-DeAngelis functional response is considered. By analyzing the corresponding characteristic equation, the local stability of a positive equilibrium is investigated. The existence of Hopf bifurcations is established. Formulae are derived to determine the direction of bifurcations and the stability of bifurcating periodic solutions by using the normal form theory and center manifold theorem. Numerical simulations are carried out to illustrate the theoretical results.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.6
• /
• pp.89-97
• /
• 2019

This study proposes a method for investigating current patents related to information communication technology and smart mobility to provide insights into future technology trends. The method is based on text mining clustering analysis. The method consists of two stages, which are data preparation and clustering analysis, respectively. In the first stage, tokenizing, filtering, stemming, and feature selection are implemented to transform the data into a usable format (structured data) and to extract useful information for the next stage. In the second stage, the structured data is partitioned into groups. The K-medoids algorithm is selected over the K-means algorithm for this analysis owing to its advantages in dealing with noise and outliers. The results of the analysis indicate that most current patents focus mainly on smart connectivity and smart guide systems, which play a major role in the development of smart mobility.

• Journal of applied mathematics & informatics
• /
• v.28 no.5_6
• /
• pp.1379-1393
• /
• 2010

In this paper, a stage-structured predator prey model (stage structure on prey) with two discrete time delays has been discussed. The two discrete time delays occur due to maturation delay and gestation delay. Linear stability analysis for both non-delay as well as with delays reveals that certain thresholds have to be maintained for coexistence. Numerical simulation shows that the system exhibits Hopf bifurcation, resulting in a stable limit cycle.