• The KIPS Transactions:PartC
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• v.11C no.1
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• pp.115-122
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• 2004

Diff-Serv is a mechanism by which network service providers can offer differing levels of network service to different traffic, in so providing quality of service (QoS) to their customers. Because this mechanism has been deployed just for fixed hosts with the Token Bucket mechanism, DiffServ have been suggested can not satisfy the mobility service or the differential serrlce for Individual traffics. In this paper, we suggest WFQ mechanism for traffic conditioner and scheduling method for monitoring the AggF(Aggregate Flow) which will be controlled in edge nodes and border routers. So it will control traffic rate dynamically and suggest efficient usability of bandwidth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.3
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• pp.639-645
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• 2007

In this study, an estimation of call demand for the internet telephony was carried out using the monthly time-series data from June 2001 to December 2004. In the estimation, the call traffic was assumed to be explained by tariff of the internet telephony service, tariff of fixed and wireless services, income, quality of service, and lagged traffic variable. The traffic is assumed to follow the partial adjustment mechanism. The estimation result shows that the call traffic demand is elastic to the tariff of the service while it is inelastic to the change of income. The qualisty of service is regarded as an important factor of demand. Also there appeared the call demand is adjusting to the change of explanatory variables with some lags.

• Korean Journal of Head & Neck Oncology
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• v.33 no.1
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• pp.39-41
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• 2017

Salivary gland tumors comprise almost 5% of head and neck malignancies, and minor salivary gland tumor which account for 10-15% of all salivary gland neoplasm are infrequently malignant. The mucoepidermoid carcinoma (MEC) is second most common tumor in minor salivary gland. It usually presents as a painless, rubbery-hard or soft mass, which may be fixed or mobile into the underlying structure. The predilection sites of intraoral MEC are palate, cheek, mandible, lip, and tongue, etc. There are very few published reports of MEC occurred in retromolar trigone. Only one case has been reported so far. Recently, we experienced a-70-year old man with a mass in retromolar trigone, which was finally diagnosed as MEC. We report the unique case with literature review.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1744-1754
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• 1998

In this paper, the data service protocol which could support data service more efficiently between mobile host and fixed host in wire network is investigated. Wireless link has high bit error rate compared with wire link. Therefore, TCP performance for the data service is degraded in wire and wireless interworking environment. Thus, to reduce performance degradation. Interworking module withsimple protocol processing function is proposed. This, interworking module analyzes the hearder information of TCP fram. If received TCP freame is a duplicated frame, TCP frame is discared. Also, if interworking moudule receives retransmission request frame is a duplicated frame, TCP freme is discarded. Also, if interworking module receives retansmission request frame, interworking module performs retransmission procedure. According to simulation results, the proposed IWF shows better performance than traditional IWF in view of delay and throughput in the wire and wireless interworking environments.

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.65-72
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• 2016

Vehicle and marine navigation which are currently being commercialized provide route guidance service by specifying a fixed position as a destination. In the route guidance service of existing navigation, if the destination has to be changed in the middle, a new destination must be designated again to obtain the navigation service. However, if the destination can't be designated, it is difficult to clearly use it. In this paper, in order to overcome the difficulties of directions in the existing navigation, a new navigation specifying moving targets as the destination has been developed to get the directions. A proposed system is that a group is made and a group manager is appointed as a destination and then a user can get the route guidance based on location of the group manager. In the service way, relationship between the group manager and user is one-to-many and relationship between the user and group manager is one-to-one. The proposed technology is able to provide services that the user can easily find the moving targets such as the positioning surrogate drivers, tracking routes and location among travelers and finding children.

• Journal of the Korea Society of Computer and Information
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• v.23 no.9
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• pp.35-42
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• 2018

In this paper, we propose an optimal streaming service method based on Hybrid CDN/P2P architecture. Recently, video streaming utilizes a CDN (Content Delivery Network) operation technique based on a Proxy Server, which is an end node located close to a user. However, since CDN has a fixed network traffic bandwidth and data information exchange among CDNs in the network is not smooth, it is difficult to guarantee traffic congestion and quality of image service. In the hybrid CDN/P2P network, a data selection technique is used to select only the data that is expected to be continuously requested among all the data in order to guarantee the QoS of the user who utilizes the limited bandwidth efficiently. In order to search user requested data, this technique effectively retrieves the storage information of the constituent nodes of CDN and P2P, and stores the new image information and calculates the deletion priority based on the request possibility as needed. Therefore, the streaming service scheme proposed in this paper can effectively improve the quality of the video streaming service on the network.

• Health Policy and Management
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• v.31 no.4
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• pp.399-408
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• 2021

The emergency medical service system in Korea was built upon the Emergency Medical Service Act, 1995 to respond adequately to be much in demand for emergency medical services. In addition, the government recognized the importance of the trauma care system and set out to plan for the designation and establishment of the regional trauma center by 2012. This study aimed to investigate features of quality management and trauma fee schedule on better understanding of trauma care system. First, quality management of the regional trauma center has been implemented by several quality programs involved in quality assessment, committee on trauma quality management, and mortality and morbidity conference. Second, the trauma fee schedule has reflected a specific quality of severe traumatic conditions and added the result to it, which are graded A, B, and C according to quality assessment. Although the government has contributed to instituting a trauma quality assessment program and trauma fee schedule for the regional trauma center, it could not lead to such a fixed standard for quality management of them. Therefore, it will promote discussion on the sustainability of the regional trauma center that requires reducing preventable trauma death rate and the way to apply comprehensive quality management.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.61 no.12
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• pp.702-704
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• 2018

The most common cause of treatment failure in oral cavity cancer is when it is found to have local recurrence, usually occurring in the ipsilateral cervical lymph node. On the contrary, it is extremely rare to find local recurrence in soft tissue metastasis (STM) in the contralateral neck. Furthermore, lung cancer and malignant lymphoma are most commonly confined to their primary sites. The poor general condition increases the likelihood of STM, which indicates bad prognosis. A 72-year-old man with a hard and fixed mass on the right submandibular space visited our clinic. He had received a wide excision with local flapreconstruction for squamous cell carcinoma in the left corner of lower lip 18 months ago. We performed the wide excision with bilateral selective neck dissection (I-III), and he was finally diagnosed as STM from contralateral lip cancer. We report this unique and rare disease entity with a literature review.

• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.310-339
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• 2015

In this paper, the possibility of a terrestrial fixed 4K UHD (Ultra High Definition) and mobile HD (High Definition) convergence broadcasting service through a single channel employing the FEF (Future Extension Frame) multiplexing technique in DVB (Digital Video Broadcasting)-T2 (Second Generation Terrestrial) systems is examined. The performance of such a service is also investigated. FEF multiplexing technology can be used to adjust the FFT (fast Fourier transform) and CP (cyclic prefix) size for each layer, whereas M-PLP (Multiple-Physical Layer Pipe) multiplexing technology in DVB-T2 systems cannot. The convergence broadcasting service scenario, which can provide fixed 4K UHD and mobile HD broadcasting through a single terrestrial channel, is described, and transmission requirements of the SHVC (Scalable High Efficiency Video Coding) technique are predicted. A convergence broadcasting transmission system structure is described by employing FEF and transmission technologies in DVB-T2 systems. Optimized transmission parameters are drawn to transmit 4K UHD and HD convergence broadcasting by employing a convergence broadcasting transmission structure, and the reception performance of the optimized transmission parameters under AWGN (additive white Gaussian noise), static Brazil-D, and time-varying TU (Typical Urban)-6 channels is examined using computer simulations to find the TOV (threshold of visibility). From the results, for the 6 and 8 MHz bandwidths, reliable reception of both fixed 4K UHD and mobile HD layer data can be achieved under a static fixed and very fast fading multipath channel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.707-715
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• 2003

In this paper, we propose a new MAC(Medium Access Control) protocol using Movable-boundary, which tries to guarantee Qos for multimedia traffic in the slotted CDMA system. In this scheme, the traffic scheduler assigns channel resource according to the packet priority per service class and adapts the Movable-boundary concept in which the minimum resource is assigned to each traffic class; the remaining resource if it is available can be assigned dynamically according to the temporal demand of other traffic classes. For performance analysis, we performed computer simulations to obtain throughput and packet loss rate and compared the results with Fixed-boundary system. We observed that the error rate of voice traffic could be maintained below a prescribed value while bursty traffic such as video source shares the same channel. In comparison with Fixed-boundary scheme, our protocol exhibits better throughput and packet loss rate performance.