• Journal of Digital Contents Society
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• v.14 no.1
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• pp.89-95
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• 2013

Many peer-to-peer (p2p) systems have been studied in distributed, ubiquitous computing environments. Distributed hash table (DHT)-based p2p systems can improve load-balancing even though locality utilization and user mobility are not guaranteed. We propose a mobile locality-based hierarchical p2p overlay network (MLH-Net) to address locality problems without any other services. MLH-Net utilizes mobility features in a mobile environment. MLH-Net is constructed as two layers, an upper layer formed with super-nodes and a lower layer formed with normal-nodes. The simulation results demonstrate that MLH-Net can decrease discovery routing hops by 13% compared with JXTA and 69% compared with Chord. It can decrease the discovery routing distance by 17% compared with JXTA and 83% compared with Chord depending on the environment.

• Journal of the Korean Society of Costume
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• v.54 no.5
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• pp.155-166
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• 2004

OP-Art was not appreciated by painters and art critics. and according1y has been forgotten in art history. But recently Op-Art is revitalized in fashion and is in its palmy days. This study intends to re-assess the value of Op-Art, by reviewing its influence on fashion design in the post-modern society To this purpose, conceptual characteristics of Op-Art was analyzed. And then, on the bases of these characteristics, the figural characteristics and the meaning of Op-Art in fashion design of post-modern society was re-explained. Op-Art is characterized as an art of flatness of picture plane which uses repetition of simple forms and colors. It is also based on trick of visual perception. Finally. it creates an impression which is flickering or vibrating by means of optical illusion. These characteristics give birth to some features such as simplicity. anonymity and mobility in the Op-Art fashion. The meanings of Op-Art in fashion design in post-modern society are as follows. First, repetition of simple units employed in Op-Art produces feeling of simplicity. which makes the Op-Art fashion works perceived as polysemy. In other words, the feeling of simplicity can be interpreted In diverse perspectives within the social context of our society. The material civilization and technology civilization, which causes the alienation and standardization of man. can be the backgrounds of the Op-Art fashion. Second, Op-Art is an art based on perspectives of spectators. Anonymity in the Op-Art fashion enhances participation of spectators. which gives Op-Art a sense of affinity. Third, through the feeling of mobility created by optical illusion techniques. the Op-Art fashion expresses the opposition to the ideal body image made by power group. In post-modern society, Op-Art in fashion gives new meaning to art. Op-Art in fashion proposes new roles of artist and spectators, and new concepts of art related with roles of human beings. Through general sensibility of men, Op-art in fashion can express new recognition of the post-modern society.

• Journal of Communications and Networks
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• v.15 no.1
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• pp.61-70
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• 2013

The increasing number of mobile users and the popularity of real-time applications make wired-wireless integrated network extremely attractive. In this case, quality of service (QoS) adaptability is particularly important since some important features of the integrated network call for QoS adaptability, such as mobility, bursty applications and so on. Traditional QoS schemes include integrated service (IntServ) and differentiated service (DiffSev) as well as their variants. However, they are not able to balance well between scalability and QoS granularity. For example, IntServ faces the scalability problem, while DiffServ can only provide coarse granular QoS. In addition, they are also unable to efficiently support QoS adaptability. Therefore, a per-packet differentiated queueing service (DQS) was proposed. DQS was originally proposed to balance between scalability and QoS granularity in wired networks and then extended to wireless networks. This paper mainly discusses how to use DQS to support QoS adaptability in wired-wireless integrated networks. To this end, we propose a scheme to determine dynamic delay bounds, which is the key step to implement DQS to support QoS adaptability. Simulation studies along with some discussions are further conducted to investigate the QoS adaptability of the proposed scheme, especially in terms of its support of QoS adaptability to mobility and to bursty real-time applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.745-759
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• 2011

In this paper, we propose the global handover mechanism that is able to provide the unlimited range of next-generation multimedia mobile services in an integrated environment. This mechanism consists of a multicast source based forwarding scheme and a global session management scheme. Global session management scheme provides LMA session information management, global mobility and route optimization. Multicast source based forwarding scheme delivers data between previously attached LMA and newly attached LMA without packet loss. In addition, this scheme removes the redundancy of buffered data. We present a performance evaluation and features analysis by the simulations using the ns-2. Global session management scheme has a less handover latency, propagation delay and signaling cost than the conventional methods. Multicast source based forwarding scheme can deliver buffer data without loss and it has less buffer size than conventional method.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.59-75
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• 2006

In this paper, we propose a congestion control scheme to control the congestion due to the mobility of ubiquitous devices on ubiquitous computing environment. Especially, this congestion control scheme provides a reverse congestion avoidance state which can classify between packet error by features of wireless network and packet dropping by congestion. Also, it provides a slow stop state which can minimize bandwidth waste due to congestion control. The proposed congestion control scheme controls more adaptive than existing congestion control schemes. The proposed congestion control scheme is designed based on DCCP(Datagram Congestion Control Protocol) being proposed by IETF(Internet Engineering Task Force) and implemented on the Linux kernel. In simulation results, the proposed congestion control scheme provides good bandwidth throughput in wireless network as well as in wired network.

• Journal of Digital Convergence
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• v.19 no.2
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• pp.425-431
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• 2021

The purpose of this study is to compare and analyze leading brands of the scooter-sharing system market of Korea, KICKGOING and Lime, in terms of user experience, and to suggest the improvement direction of the applications and scooters of those two services. The assessment was conducted in such a way that the experimental group using scooter-sharing system over a certain frequency would choose the specific service they use most frequently, and complete a questionnaire: based on the reorganized version of the Peter Morville's Honeycomb Model. Based on the results of the experiment, We drew a conclusion that the services need to add navigation features in the application, to provide more simple procedures for reporting breakdown or accident and browsing insurance information, and to improve the user and pedestrian safety levels by gamification, et cetera. We expect this study to help the fast-growing smart mobility market and scooter-sharing systems that represent the market develop into a user-centered way.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.17-28
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• 2021

Recently, eVTOL, the next-generation of eco-friendly transportation, has been in the spotlight due to global warming along with traffic jams in large cities of many countries. This study benchmark the external features of Hyundai Motors S-A1, a compound eVTOL combined fixed and tilt rotors among many types of eVTOLs, to create the basic configuration using reverse design techniques. Basic configurations were created using CATIA and aerodynamic analyses were performed using the aircraft design and aerodynamic analysis programs, OpenVSP, XFLR5, and the aircraft wetted area, drag, and lift were calculated after selecting the airfoil, incidence angle, and dihedral and anhedral angles through trade study. Also, required powers were estimated for completing the given mission profile and components weight and the total weight were predicted using the estimation formula and data survey.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.1
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• pp.29-37
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• 2012

Introduction: Fibrous-osseous lesions of the jaws are difficult to diagnose precisely until excised biopsy results are found, so they might be confused with malignant lesions. This clinical study focused on the diagnostic aids of lesions that demonstrate different clinical, radiologic, and histological findings. Materials and Methods: A total of 16 patients with benign fibrous-osseous lesions on the jaws (6 fibrous dysplasias, 6 ossifying fibromas, 3 cemental dysplasias, and one osteoblastoma) were reviewed. Nine patients with malignant fibrous-osseous lesions (8 osteosarcomas and one Ewing's sarcoma) were also retrospectively reviewed. Results: Osteosarcoma patients complained of facial swelling and tooth mobility. The radiographic findings showed the irregular resorption of cortical bone and periosteal reactions. Histological features included cellular pleomorphism and atypical mitosis. An Ewing's sarcoma patient complained of tooth mobility and facial swelling. Onion-skin appearance and irregular expansile marginal bony radiolucency were seen in the radiography. Fibrous dysplasia patients complained of facial swelling and asymmetry. The radiographic features were mostly ground-glass radiopacity. Histological findings showed a bony trabeculae pattern surrounded by fibrous ground substances. Ossifying fibroma patients complained of buccal swelling and jaw pains, showing expanded cortical radiolucent lesions with a radiopaque margin. Histological findings were revealed as cellular fibrous stroma with immature woven bones. In cemental dysplasia, most of their lesions were found in a routine dental exam. Well-circumscribed radiopaque lesions were observed in the radiography, and cementum-like ossicles with fibrous stroma were seen in the microscopy. An osteoblastoma patient complained of jaw pain and facial swelling. Radiographic findings were mottled, dense radiopacity with osteolytic margin. Trabeculae of the osteoid with a vascular network and numerous osteoblasts with woven bone were predominantly found in the microscopy. Conclusion: Our study showed similar results as other studies. We suggest the clinical parameters of diagnosis and treatment for malignant and benign fibrous-osseous lesions of the jaws.

• Journal of the Korea Society for Simulation
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• v.31 no.3
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• pp.55-61
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• 2022

Currently police and fire departments use a Network/Wifi/GPS based emergency location positioning system established by mobile carriers to directly link with the device of the people who request the rescue to accurately position the expected location in the call area. However in the case of mountain rescue it is difficult to rescue the victim in golden time because the location of the search area cannot be limited when the victim is located in a radio shadow area of the mountain or the device power is off and this situation become worse if victim fail to report 911 by himself due to the injury. In this paper, we are expected to solve the previous problem by propose the mobile telecommunication forensic simulator consist of time series of cell information, human mobility model which include some general and specific features (age, gender, behavioral characteristics of victim, etc.) and intelligent infer system. The results of analysis appear in heatmap of polygons on the map based on the probability of the expected location information of the victim. With this technology we are expected to contribute to rapid and accurate lifesaving by reducing the search area of rescue team.

• Journal of vocational education research
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• v.35 no.4
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• pp.47-61
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• 2016

The purpose of this study is to analyze student and university features affecting outcome in labor market after university graduates. For accomplish this, multi-level analysis modeling with HLM(Hierarchical Linear Modeling) was adopted. GOMS(Graduates Occupational Mobility Survey) 2013 data were used for this study, and we added the Information Service of Education data for university information. The result of analysis were as follows. (a) Factors affecting outcome in labor market after university graduate were both student and university features. Significant features were house income, gender, academic major, GPA, and satisfaction in view point of student level. In university level, there were significant variables likes foundation, location, education costs, school type, and satisfaction. (b) We found the different significant variables between student and school level in the participations on the university career program. Significant features were job-experience and job-exhibition in student level, but there were no significant after adding variable in school level. In the school level, there were significant in subjects related career and job, job-exhibition, and consulting.