• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.9
• /
• pp.1776-1785
• /
• 2015

Content Centric Network (CCN) has been introduced as a new paradigm due to a shift of users's perspective of using Internet from host-centric to content-centric. On the other hand, a demand for video streaming has been increasing. Thus, Adaptive streaming has been introduced and researched for achieving higher user's satisfaction. If an architecture of Internet is replaced with CCN architecture, it is necessary to consider adaptive video streaming in CCN according to the demand of users. However, if the same rate decision algorithm used in Internet is deployed in CCN, there are a limitation of utilizing content store (CS) in CCN router and a problem of reflecting dynamic requirements. Therefore, this paper presents a framework adequate to CCN protocol and cache utilization, adapting content naming method of exploiting regular expression to the rate decision algorithm of the existing adaptive streaming. In addition, it also improves the quality of video streaming and verifies the performance through dynamic expression strategies and selection algorithm of the strategies.

• Journal of KIISE:Information Networking
• /
• v.30 no.5
• /
• pp.656-667
• /
• 2003

Congestion control is a key task in reliable multicast along with error control. However, existing tree-based congestion control schemes such as MTCP and TRAMCC are designed for one-to-many reliable multicast and have some drawbacks when they are used for many-to-many reliable multicast. We propose an efficient congestion control mechanism, TMRCC, for tree-based many-to-many reliable multicast protocols. The proposed scheme is based on the congestion windowing mechanism and a rate controller is used in addition. The feedback for error recovery is exploited for congestion control as well to minimize the overhead at the receivers. The ACK timer and the NACK timers are set dynamically reflecting the network condition changes. The rate regulation algorithm in the proposed scheme is designed to help the flows sharing the same link to achieve the fair share quickly The performance of the proposed scheme is evaluated using ns-2. The simulation results show that the proposed scheme outperforms TRAMCC in terms of intra- session fairness and shows good level of responsiveness, TCP-friendliness, and scalability. In addition, we implemented the proposed scheme by integrating with GAM that is one of many-to-many reliable multicast protocols and evaluated the performance in a laboratory-wide testbed.

• The Journal of the Convergence on Culture Technology
• /
• v.10 no.3
• /
• pp.923-932
• /
• 2024

The purpose of this study is to explore the direction of teaching and learning in the era of science and technology. The conclusion is as follows: From the perspective of new materialism, the direction of teaching and learning first emphasizes the importance of learning experience. Second, a teaching method that emphasizes giving meaning is needed. Third, there is a need to consider various perspectives and backgrounds. The direction of teaching and learning in the era of phenomenology is, first, the meaning and meaning of learning is important. Second, it emphasizes the role of independent learners. Third, diverse experiences must be integrated. Fourth, a flexible approach is needed depending on the environment and situation. Rather than a fixed teaching method, it is necessary to use a variety of teaching strategies according to the situation and needs of the learner. From the perspective of actor network theory, the direction of teaching and learning needs to first embrace a variety of actors. Second, there is a need to understand the role of the mediator actor. Third, there is a need to emphasize the dynamic aspect of the network. Fourth, there is a need to emphasize interaction and giving meaning. Fifth, there is a need to strengthen interaction with technology. Sixth, there is a need to create a non-linear and open learning environment. The direction of society and teaching and learning presented in Trend Korea 2024 considers time as a precious resource in a divided society, and teaching and learning must adapt and develop in a useful direction in a changing environment.

• Archives of design research
• /
• v.20 no.3 s.71
• /
• pp.49-60
• /
• 2007

As the world is in the age of globalization and information, we observe diverse changes in the market environment. Since wide-spread internet services and global networks made ubiquitous learning and business possible, equalizing consumers' ideology and preference, new trend and life style could be introduced easily. This study stipulates on the theoretical concept of the wellbeing consumer and LOHAS consumer. Consumers of LOHAS could be sampled out through pre-questionnaire targeting at selected food, clothing, and shelter based on companies of both wellbeing and general brands. Through this it is attempted to measure wellbeing emotion, recognition quotient of emotion and reason, affirmation and negation, mental emotion quotient, and preference in order to find out their value and to ultimately come up with what web design should be aiming at. Conclusions are as follows: Firstly, consumers easily recognize emotional identification from the web pages of wellbeing brand, rather than that of general brands. Secondly, what web pages of wellbeing brand recognize is reason, not emotion. Thirdly, the design of wellbeing brands scored higher than those of general brands in terms of positive aspects such as hospitality and familiarity, and high mental emotion quotient could not affect the consumers' preference toward web design. Fourthly, wellbeing brands win more preference than general brands do, and preference becomes higher after customers' visit to web pages basically. Lastly, sampled emotional adjectives toward the web designs of wellbeing brands marked a aesthetic graph figure, without leaning toward an active or stable one. It is expected that this study can serve as a groundwork to create proper strategies to actively involve consumers in industrial sphere.

• Journal of Korean Society for Geospatial Information Science
• /
• v.8 no.1 s.15
• /
• pp.51-63
• /
• 2000

Dynamic traffic assignment(DTA) has been a topic of substantial research during the past decade. While DTA is gradually maturing, many aspects of DTA still need improvement, especially regarding its formulation and solution algerian Recently, with its promise for In(Intelligent Transportation System) and GIS(Geographic Information System) applications, DTA have received increasing attention. This potential also implies higher requirement for DTA modeling, especially regarding its solution efficiency for real-time implementation. But DTA have many mathematical difficulties in searching process due to the complexity of spatial and temporal variables. Although many solution algorithms have been studied, conventional methods cannot iud the solution in case that objective function or constraints is not convex. In this paper, the genetic algorithm to find the solution of DTA is applied and the Merchant-Nemhauser model is used as DTA model because it has a nonconvex constraint set. To handle the nonconvex constraint set the GENOCOP III system which is a kind of the genetic algorithm is used in this study. Results for the sample network have been compared with the results of conventional method.

• Journal of the Korean Society for Railway
• /
• v.19 no.3
• /
• pp.388-396
• /
• 2016

The metropolitan subway network of Seoul has gone through many evolutionary processes in past decades to disperse the floating population and improve the traffic flow. In this study, we analyzed how the structural characteristics and the efficiency of the subway network have changed according to the dynamic evolutionary processes of the metropolitan subway network of Seoul. We have also proposed new measures that can be used to characterize the structural properties of the subway network more practically. It is shown that the global efficiency is about 74%, which is higher than those of subway networks of foreign countries. It should also be considered that passenger flow between stations is even higher, at about 85%. Since the private lines, including line 9, the New Bundang line, the Uijeongbu line, and the Ever line do not release their traffic data since September, 2013, only 5 years of data from September, 2008 to September, 2013 is available. So, in this study we limit the analysis period to these 5 years.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.8B
• /
• pp.707-718
• /
• 2008

The methodology of classifying traffics is changing from payload based or port based to machine learning based in order to overcome the dynamic changes of application's characteristics. However, current state of traffic classification using machine learning (ML) algorithms is ongoing under the offline environment. Specifically, most of the current works provide results of traffic classification using cross validation as a test method. Also, they show classification results based on traffic flows. However, these traffic classification results are not useful for practical environments of the network traffic monitoring. This paper compares the classification results using cross validation with those of using split validation as the test method. Also, this paper compares the classification results based on flow to those based on bytes. We classify network traffics by using various feature sets and machine learning algorithms such as J48, REPTree, RBFNetwork, Multilayer perceptron, BayesNet, and NaiveBayes. In this paper, we find the best feature sets and the best ML algorithm for classifying traffics using the split validation.

• Journal of Advanced Navigation Technology
• /
• v.16 no.1
• /
• pp.89-95
• /
• 2012

This paper introduces domestic and international trends and researches related with U-Greenhouse systems. USN (Ubiquitous Sensor Networks), along with the development of networks as well as science and technology, is a new computing paradigm which is the convergence of user-oriented physical activity space and virtual space of electronics and computing and also provides services according to change in surrounding environment at anytime and anywhere. The U-Greenhouse system is to apply USN to agricultural production, logistics and distribution management which are relatively insufficient to utilize IT technology. Thus, applying u-IT technology to agriculture can reinforces international competitiveness of the agricultural sector through the effects such as cost cutting as a rise in output, logistics and distribution management.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.42 no.1
• /
• pp.64-76
• /
• 2017

Routing in mobile ad hoc networks (MANETs) is highly challenging because of the dynamic nature of network topology. AntHocNet is a bio-inspired routing protocol for MANETs that mimics the foraging behavior of ants. However, unlike many other MANET routing protocols, the paths constructed in AntHocNet are unidirectional, which requires a separate path setup if a route in the reverse direction is also required. Because most communication sessions are bidirectional, this unidirectional path setup approach is often inefficient. Moreover, AntHocNet suffers from looping problems because of its property of multiple paths and stochastic data routing. In this paper, we propose a modified path setup procedure that constructs bidirectional paths. We also propose solutions to some of the looping problems in AntHocNet. Simulation results show that performance is significantly enhanced in terms of overhead, end-to-end delay, and delivery ratio when loops are prevented. Performance is further improved, in terms of overhead, when bidirectional paths setup is employed.

• Journal of Digital Contents Society
• /
• v.10 no.1
• /
• pp.1-10
• /
• 2009

One important issue to generalize the ubiquitous paradigm is the development of user-centralized and intelligent ubiquitous computing systems. Sharing knowledge and correct communication between users and devices are needed to be aware of continuous changed context information and infer services for which users are suited. The goal of this paper is to describe and manage effectively the meaning of services or data which each device offers for interaction between users and devices based on semantic relationships and reasoning. In this paper, we represent semantic data using OWL and design a ubiquitous based intelligent system. We propose some index structures and strategies to process queries classified by each subsystem and adopt labeling schemes to identify classes and resources in the semantic data. We can find devices which satisfies various user's requests exactly and quickly using the proposed strategies.