• Journal of KIISE:Databases
• /
• v.33 no.3
• /
• pp.299-309
• /
• 2006

Due to the rapid development in mobile communication technologies, the usage of mobile devices such as cell phone or PDA becomes increasingly popular. As different devices require different applications, various new services are being developed to satisfy the needs. One of the popular services under heavy demand is the Location-based Service (LBS) that exploits the spatial information of moving objects per temporal changes. In order to support LBS efficiently, it is necessary to be able to index and query well a large amount of spatio-temporal information of moving objects. Therefore, in this paper, we investigate how such location information of moving objects can be efficiently stored and indexed. In particular, we propose a novel location encoding method based on hierarchical administrative district information. Our proposal is different from conventional approaches where moving objects are often expressed as geometric points in two dimensional space, (x,y). Instead, in ours, moving objects are encoded as one dimensional points by both administrative district as well as road information. Our method is especially useful for monitoring traffic situation or tracing location of moving objects through approximate spatial queries.

• Journal of Digital Convergence
• /
• v.11 no.3
• /
• pp.273-277
• /
• 2013

Phishing attacks have been implemented in smarter, more advanced ways with the passage of time. Hackers use intelligent phishing attacks to take over computers and to penetrate internal networks in major organizations. So, in this paper, a model for a prevention of phishing attack spread is conceptual designed in order to protect internal users and sensitive or important information from sophisticated phishing attacks. Internal users simultaneously utilize both external web and organizational mail services. And hackers can take the both side equally as a vector. Thus, packets in each service must be monitored and stored to recognize threatening elements from both sides. The model designed in this paper extends the mail server based security structure used in conventional studies for the protection of Internet mail services accessed by intranet users. This model can build a list of phishing sites as the system checks e-mails compared to that of the method that directly intercepts accesses to phishing sites using a proxy server, so it represents no standby time for request and response processes.

• Journal of KIISE:Information Networking
• /
• v.29 no.4
• /
• pp.375-385
• /
• 2002

The IETF has defined the Intserv model and the RSVP signaling protocol to improve QoS capability for a set of newly emerging services including voice and video streams that require high transmission bandwidth and low delay. However, since the current Intserv model requires each router to maintain the states of each service flow, the complexity and the overhead for processing packets in each rioter drastically increase as the size of the network increases, giving rise to the scalability problem. This motivates our work; namely, we investigate and devise new control schemes to enhance the scalability of the Intesev model. To do this, we basically resort to the SCORE network model, extend it to fairly well adapt to the three services presented in the Intserv model, and devise schemes of the QoS scheduling, the admission control, and the edge and core node architectures. We also carry out the computer simulation by using ns-2 simulator to examine the performance of the proposed scheme in respects of the bandwidth allocation capability, the packet delay, and the packet delay variation. The results show that the proposed scheme meets the QoS requirements of the respective three services of Intserv model, thus we conclude that the proposed scheme enhances the scalability, while keeping the efficiency of the current Intserv model.

• Korean Journal of Social Welfare Studies
• /
• v.47 no.4
• /
• pp.333-360
• /
• 2016

Social Impact Bonds(SIBs) has emerged as a promising way to finance proven social services programs, fund what works, and drive government accountability and has increased fast. In this context, this study examines and classifies the structure of SIB focusing key criteria of the main steps through two-step cluster analysis. Analysis results are as follows. First, the main commissioners of SIB are the ministries of the central government. And in terms of the stage of invest, there are usually two or three investors mainly consisting of social finance organizations. Second, in terms of target and age of SIB beneficiaries, it focuses on the adolescent and youth. Third, in the outcome evaluation stage, the results show that in most cases outcome payments are determined by a validation of service provider or government administrative data. However, the rate of payments are based on the comparison of the program beneficiaries to other comparable groups is 23.8%. Finally, The results of two-step cluster analysis are as; 'mix of central government and social finance organization', 'multiple agent including private organization', and 'multiple social provider'. Among three types, 'multiple agent including private organization' shows the most active participation between agents and the most systematic outcome measurement and management. The results of this study imply that the importance of the method to manage and measure outcome in SIB structure. Moreover, the consist of commissioners or investors is needed to expanded more.

• 한국HCI학회:학술대회논문집
• /
• 2007.02a
• /
• pp.1051-1056
• /
• 2007

In current web-based systems, it is generally recognized that one way flow of information from providers to users can cause the static problem of document structure. Therefore, information update frequency and interaction between providers and users are quiet slow. Monopolized information can obstruct the free user's access and heterogeneous format and different protocols also make users difficult to retrieve and to collect information. To resolve these problems, in this study, we introduce the Web 2.0 to move toward the user's participation and share based on the social network and the OAI protocol to improve the free access and the interoperability on bibliographic information for Life Science and then design the bibliographic information network for life science. This network has four main functions such as: 1) Open Repository function that can make up user community for sharing and data exchange. Data such as article, seminar material, research note and research report are considered in design. 2) Open Collection function that can collect and store the metadata on distributed bibliographic information networks, 3) Open Access function that can manage the metadata in the open access environment, and 4) Administration function that can monitor the user activity and statistics and can inspect the registered data.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.5
• /
• pp.708-720
• /
• 1993

The new preventive control mechanisms for traffic management in BISDN/ATM networks can be divided into Connection Admission Control(CAC), Usage Parameter Control (UPC), and Priority Control. Of these mechanism, Usage Parameter Control continuously monitors the parameters admitted in the network's entry point to guarantee quality of service of connections already admitted. Upon detecting traffic that violates the negotiated parameter, it takes the necessary control measures to prevent congestion. Among these traffic control methods, this paper focuses on the Usage Parameter Control method, and proposes and designs GRACE-LB(Guaranteed Rate Acceptance & Control Element-using Leaky Bucket) which improves upon existing UPC models. GRACE-LB modifies the previous LB model by eliminating the cell buffer, dividing the token Pool into two pools, Long-term pool, Short-term pool, and changing the long-term token generating form using 'Cycle Token' into the same bursty form as the traffic source. Through this, GRACE-LB achieves effective control of the Average Bit Rate(ABR) and burst duration of bursty multimedia traffic which previous LB models found difficult to control. Also, since GRACE-LB can e implemented using only simple operations and there are no cell buffers in it, it has the merit of being easily installed at any place.

• The Journal of Bigdata
• /
• v.4 no.2
• /
• pp.159-173
• /
• 2019

Last-Mile delivery optimization plays a key role in the urban supply chain operation, which is the most expensive and time-consuming and most complicated part of the whole delivery process. The urban consolidation center (UCC) is regarded as a significant asset for supporting customer demand in the last-mile delivery service. It is the key benefit of UCC to improve the load balance of vehicles and to reduce the total traveling distance by finding the better route with the well-organized multi-leg vehicle journey in the urban area. This paper presents the model using multiple scenario analysis integrated with mathematical optimization techniques using Geographic Information System (GIS). The model aims to find the best solution for the distribution network consisted of DC and UCC, which is applied to the case of Ulaanbaatar Mongolia. The proposed methodology integrates two sub-models, location-allocation model and vehicle routing problem. The multiple scenarios devised by selecting locations of UCC are compared considering the general performance and delivery patterns together. It has been adopted to make better decisions the quantitative metrics such as the economic value of capital cost, operating cost, and balance of using available resources. The result of this research may help the manager or public authorities who should design the distribution network for the last mile delivery service optimization using UCC within the urban area.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2013.06a
• /
• pp.214-215
• /
• 2013

Current competition among companies than regional, the time constraints, it is globalization, Tilt the efforts of many to be operated by building the efficient distribution system to reduce logistics costs and improve customer service it is reality's there. Therefore, the need for industrial complexes environmentally friendly can be cost competitive companies perform cavitation region's increased. To build the distribution center these logistics system through a joint of freight and appropriate policy is required. In particular, efficient operation through the system construction of industrial complexes in the logistics system is very important in terms of friendly low-cost urban logistics, the environment. Since the traffic volume which is Jipufa and utilization of network is transported by a more appropriate technicians and means suitable operating model can efficiency is improved. However, despite these advantages, research network design has not been actively conducted due to the complexity of the problem. Therefore, in this study, by analyzing the logistics system, and presents the operating model through a simulation and basic settings for the model of the logistics complex based on the analysis result, the construction of infrastructure of logistics industry complex it is intended to present the article.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.8
• /
• pp.3672-3679
• /
• 2012

Vehicle Ad hoc Network (VANET) is next-generation network technology to provide various services using V2V (Vehicle-to-Vehicle) and V2I (Vehicle-to-Infrastructure). In VANET, many researchers proposed various studies for the safety of drivers. In particular, using the emergency message to increase the efficiency of traffic safety have been actively studied. In order to efficiently transmit to moving vehicle, to send a quick message to as many nodes is very important via broadcasting belong to communication range of vehicle nodes. However, existing studies have suggested a message for transmission to the communication node through indiscriminate broadcasting and broadcast storm problems, thereby decreasing the overall performance has caused the problem. In addition, theses problems has decreasing performance of overall network in various form of road and high density of vehicle node as urban area. Therefore, this paper proposed Clustering based Routing Algorithm (CBRA) to efficiently transmit emergency message in high density of vehicle as urban area. The CBRA managed moving vehicle via clustering when vehicle transmit emergency messages. In addition, we resolve linkage problem between vehicles according to various form of road. The CBRA resolve link brokage problem according to various form of road as urban using clustering. In addition, we resolve broadcasting storm problem and improving efficacy using selection flooding method. simulation results using ns-2 revealed that the proposed CBRA performs much better than the existing routing protocols.

• The KIPS Transactions:PartC
• /
• v.10C no.3
• /
• pp.287-294
• /
• 2003

Authentication and authorization are essential functions for the security of distributed network environment. Authorization is determining and to decide whether a user or process is permitted to perform a particular operation. In this paper, we design an authorization mechanism to make a system more effective with Kerberos for authentication mechanism. In the authorization mechanism, Kerberos server operates proxy privilege server. Proxy privilege server manages and permits right of users, servers and services with using proposed algorithm. Also, privilege attribute certificate issued by proxy privilege server is used in delegation. We designed secure kerberos with proposed functions for effective authorization at the same time authentication of Kerberos mechanism.