• KIPS Transactions on Computer and Communication Systems
• /
• v.10 no.12
• /
• pp.319-328
• /
• 2021

With popularization of services for massive content, the fundamental limitations of TCP/IP networking were discussed and a new paradigm called Information-centric networking (ICN) was presented. In ICN, content is addressed by the content identifier (content name) instead of the location identifier such as IP address, and network nodes can use the cache to store content in transit to directly service subsequent user requests. As the user request can be serviced from nearby network caches rather than from far-located content servers, advantages such as reduced service latency, efficient usage of network bandwidth, and service scalability have been introduced. However, these advantages are determined by how actively content stored in the cache can be utilized. In this paper, we 1) introduce content access schemes in Named-data networking, one of the representative ICN architectures; 2) in particular, review the schemes that allow access to cached content away from routing paths; 3) conduct comparative study on the performance of the schemes using the ndnSIM simulator.

• Korean Journal of Health Education and Promotion
• /
• v.25 no.5
• /
• pp.21-38
• /
• 2008

Objective: This study examined the use of mental health helping systems among college students in Korea. A behavioral model of health service utilization was applied to examine factors influencing different types of helping systems. Methods: A total of 454 college students from four universities participated in the survey. A self-administered questionnaire measuring help-seeking behaviors including formal health and mental health services, informal helping system, peer group, and family support was used. Results: Respondents frequently turn to family members and peer group when in need, and age, sex, mental Health status, and attitude and knowledge on mental illness were significant factors affecting help-seeking behaviors of Korean students. While older students and those with more severe symptoms were more likely to seek help from formal resources, students with more severe symptoms were less likely to seek help from informal resources. Male students and those with negative attitude toward mental illness were less likely to ask peer groups for help. Conclusions: Study results indicate that informal resources and peer groups can be significant sources of social support for individuals in their late adolescence and young adulthood, however, their role as gateways to professional help is limited. Student counseling centers should take on a more active role in reaching out; implications for developing peer leaders as counselors and self-help groups are discussed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.7
• /
• pp.1306-1312
• /
• 2017

The route request (RREQ) packet is selectively re-broadcasted in the routing protocols that improve the broadcast storm problem of the ad-hoc on-demand routing protocol (AODV). However, in a low node density scenario, the connectivity of these selective rebroadcast schemes becomes less than that of the AODV. In order to clarify the requirements of these selective re-broadcast routing protocols, it is necessary to investigate the relationship between the node density and the connectivity. In this paper, we drive a probability to preserve the connectivity of the GAODV at an intermediate rebroadcast node. In addition, we present an intuitive method to approximate the end-to-end connectivity of the GAODV. We draw the required node density to guarantee the connectivity of 0.9 and 0.99 through computer simulations, and verify the validity of the derived theoritical connectivity by comparing with the simulation results.

• Journal of Digital Convergence
• /
• v.15 no.8
• /
• pp.341-349
• /
• 2017

CCN proposes that intermediate network nodes on a network path for a transmitted data-packet cache the data-packet. If the nodes receive request packets for the cached data, the nodes can directly respond to the request-packets using the cached data. Since a request-packet can be responded by one of the intermediate nodes on a path of the request-packet, both faster response time and decreased data transmission amount are expected comparing to the existing host centric networking. However, CCN is vulnerable against forgery attacks because data-packet receivers cannot identify a data provider. Hence, a data authentication scheme is essentially needed to make CCN more secure. But such a data authentication process is one of the main causes of CCN-based service delays. This paper first analyzes the problems of a CCN data authentication scheme, then proposes an improved authentication operation scheme for efficiently authenticating data, and finally evaluates its performance.

• Journal of the Korea Computer Industry Society
• /
• v.2 no.11
• /
• pp.1453-1464
• /
• 2001

Explosive growth of Internet populations results performance degradations of web service. Popular web sites cannot provide proper level of services to many requests, and such poor services cannot give user a satisfaction. Web caching, the remedy of this problem, reduces the amount of network traffic and gives fast response to user. In this paper, we analyze the characteristics of web cache traffics using traces of NLANR(National Laboratory for Applied Network Research) root caches and Education network cache in Seoul National University. Based on this analysis, we suggest a method of prefetching and we discuss the gains of our prefetching. As a result, we find proposed prefetching enhances hit rate up to 3%, response time up to 5%.

• Journal of the Korea Society for Simulation
• /
• v.18 no.1
• /
• pp.35-40
• /
• 2009

The reliability of processing the distributed application becomes more and more important issues in distributed network as the usage of distributed network increases. Because the distributed network applications are processed in the available resources of Internet. It is important factors that the user can efficiently access the available resources and processed results can be delivered to the user of job request. Therefore in this paper, we suggested the survivability factor for sending data safely whether it can be efficiently accessed between the user and available resource which processes the distributed application. And evaluated the performance of the suggested factor using the data transmission time. Also we suggested the transmission algorithm for safe transmission using the survivability factor.

• Journal of Korea Spatial Information System Society
• /
• v.10 no.4
• /
• pp.1-10
• /
• 2008

In wireless internet, the location information of the user is one of the important resources for many applications. One of these applications is Location-Based Services (LBSs) which are being popular. Because, in the LBS system, users request a location-based query to LBS servers by sending their exact location, the location information of the users can be misused by adversaries. In this regard, there must be a mechanism which can deal with privacy protection of the users. In this paper, we propose a cloaking method considering both features of K-anonymity and L-diversity. Our cloaking method creates a minimum cloaking region by finding L number of buildings (L-diversity) and then finding number of users (K-anonymity). To support this, we use a R*-tree based index structure and use filtering methods especially for the m inimum cloaking region. Finally, we show from a performance analysis that our method outperforms the existing grid based cloaking method.

• Journal of Korea Spatial Information System Society
• /
• v.11 no.2
• /
• pp.151-161
• /
• 2009

In Location-Based Services (LBSs), users requesting a location-based query send their exact location to a database server and thus the location information of the users can be misused by adversaries. Therefore, a privacy protection method is required for using LBS in a safe way. In this paper, we propose a new cloaking region generation algorithm using grids for privacy protection in LBSs. The proposed algorithm creates a m inimum cloaking region by finding L buildings and then performs K-anonymity to search K users. For this, we make use of not only a grid-based index structure, but also an efficient pruning techniques. Finally, we show from a performance analysis that our cloaking region generation algorithm outperforms the existing algorithm in term of the size of cloaking region.

• Spatial Information Research
• /
• v.18 no.3
• /
• pp.53-62
• /
• 2010

Recent development in wireless communication technology, like GPS, and mobile equipments, like PDA and cellular phone, make location-based services (LBSs) popular. However, because, users continuously request a query to a server in the LBSs by using their exact locations, privacy information could be in danger. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, we, in this paper, propose a grid-based cloaking area creation scheme supporting continuous LBSs in peer-to-peer environment. The proposed scheme creates a cloaking area by using Chord protocol, so as to support the continuous LBSs in peer-to-peer environment. Finally, we show from a performance analysis that our cloaking scheme outperforms the existing cloaking schemes, in terms of service time.

• Journal of the Korea Convergence Society
• /
• v.11 no.1
• /
• pp.17-23
• /
• 2020

Recently, due to increases in the numbers of nursing students, there are many cases of clinical practice in remote areas other than in hospitals near a school. In this regard, the Korea Institute of Nursing Evaluation emphasizes the securing of safety, the provision of regulations, and countermeasures related to long-term practices of nursing students. The purpose of this study is to develop a safety management application for nursing students who are practicing at a distance. This application configuration consists of accommodation location information, nursing student location information check, and notification of the professor in charge. The location information of nursing students was based on their location on weekdays from 10 pm to 11 pm, due to the work schedule of the nursing students. For this reason, nursing students can use this app after their clinical practice; if the student is out of the safety radius or there is a problem, a risk notification can be provided through a service and a rescue request can be made.