• ETRI Journal
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• v.37 no.6
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• pp.1087-1095
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• 2015

Mobility management is important in mobile cellular networks. In this study, we considered an enhanced location-based registration (ELR) method. In the ELR method, even when a mobile phone enters a cell to find that the cell is already on its list (of visited cells) and then updates its main counter, it does not remove any cells from the list (memory space permitting), which gives better performance than the location-based registration (LR) method. However, the location registration cost of the ELR method is still high, and there is a lot of room for improvement with regards to this matter. We now propose an improved version of the ELR method; namely, the improved ELR (iELR). In the iELR method, when a mobile phone enters a cell to find that the cell counter value is less than the main counter value, or when a mobile phone enters a cell to register its location, it updates the main counter and the cell counter values as much as possible to reduce the future need for registrations. We show that our proposed iELR method provides better performance than the ELR method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.11
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• pp.47-55
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• 2004

In this paper, an enhanced time-based registration method is proposed. The method reduces the registration cost when a mobile terminal stays in a cell for a long time. We also analyze the performance of the proposed method numerically. In the analysis, we assume Poisson call arrival distribution and exponential cell resident time. From the analysis we calculate the optimal time-interval. Additionally, limit cost analysis is made to investigate the behaviors in the limit conditions. To compare the performance of the proposed method with the original time-based registration method, we analyze the performance of the original time-based registration method. In the comparisons, we see that the proposed enhanced time-based registration method has better performance and is applicable to the PCS systems.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.91-99
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• 2016

A certificate revocation list(CRL) should be distributed quickly to all the vehicles in the network to protect them from malicious users and malfunctioning equipments as well as to increase the overall security and safety of vehicular networks. However, a major challenge is how to distribute CRLs efficiently. In this paper, we propose a novel Regional CRL distribution method based on the vehicle location registration locally to manage vehicle mobility. The method makes Regional CRLs based on the vehicles' location and distributes them, which can reduce CRL size and distribution time efficiently. According to the simulation results, the proposed method's signaling performance of vehicle's registration is enhanced from 22% to 37% compared to the existing Regional CRL distribution method. It's CRL distribution time is also decreased from 37% to 67% compared to the existing Full CRL distribution method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.64-70
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• 2003

In order to provide seamless wireless Internet service, the basic mobile IP protocol should be enhanced to solve packet loss problem from large registration latency because frequent handoffs occur in cellular networks. In this paper, we suggest a new micro-mobility management protocol based on MPLS while supporting Qos, and evaluate its performance using simulation. We use MPLS label switching techniuqe in cellular access networks to simplify location management and speed up packet transmission. We adopt context transfer procedure to minimize the delay needed to attain prior level of service after handoff Packet loss can be minimized during handoff by transmitting received packets from old BSLER to new BSLER using a spliced LSP between them. Simulation results show that the proposed MPLS-based micro-mobility management protocol provides a seamless handoff and supports QoS of user traffic.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2312-2317
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• 2017

Museums are converging with digital technology to convey information to viewers in various ways. Augmented reality technology enhances virtual objects seamlessly in the real world, and provides a high sense of immersion and realism because it can use various senses of users in combination with information providing role of exhibits. However, the location-based augmented reality may cause the inaccurate registration of the virtual object with the real world due to the error of the GPS information, and the vision-based augmented reality can be enhanced at the position where the marker is placed. To solve this problem, we implemented the exhibition contents that interact with the real world by using the developed project tango. The exhibited contents were based on Lenovo Phab 2 Pro and Project Tango SDK in Unity 3D. Visitors were able to improve immersion and realism in exhibition contents, and it would be able to combine with various exhibition fields such as shopping malls as well as museums.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.942-955
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• 2000

This paper proposes enhanced designs of global service logic and information flow for the mass-call based IN service, which increase call completion rates and optimize the resource in joint wired and wireless networks. In order to hanve this logic implemented, we design a Dynamic Queue Manager(DQM) applied to the call queuing service feature in the Service Control Point(SCP). In order to apply this logic to wireless service subscribers as well as wired service subscribers, the service registration flags between the Home Location Register(HLR) and the SCP are managed to notify the DQM of the corresponding service subscribers’ mobility. Hence, we present a dynamic queue management mechanism, which dynamically manages the service group and the queue size based on M/M/c/K queueing model as the wireless subscribers roam the service groups due to their mobility characteristics. In order to determine the queue size allocated by the DQM, we simulator and analyze the relationship between the number of the subscriber’s terminals and the drop rate by considering the service increment rate. The appropriate waiting time in the queue as required is simulated according to the above relationship. Moreover, we design and implement the DQM that includes internal service logic interacting with SIBs(Service Independent building Blocks) and its data structure.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.186-198
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• 2016

HPAI(Highly Pathogenic Avian Influenza) is a contagious animal disease that spreads rapidly by diffusion after the first occurrence. The disease has brought tremendous social costs and economic losses. KAHIS (Korea Animal Health Information System) is the integrated system for supporting the task of preventing epidemics. They provide decision-support information, recording vehicle visiting times and facility location, etc., which is possible by enforcing registration of all livestock related facilities and vehicles. KAHIS has accumulated spatial and temporal information that enables effective tracing of potential disease trajectories and diffusion through vehicle movements. The contact network is created utilizing spatial and temporal information in KAHIS to inform facility connection via vehicle visitation. Based on the contact network, it is possible to infer spatial and temporal mechanism of disease spread and diffusion. The study objective is to empirically demonstrate how to utilize primary spatial and temporal information in KAHIS in the form of the contact network. Based on the contact network, facilities with the possibility of infection can be pinpointed within the potential spatial and temporal extent where the disease has spread and diffused. This aids the decision-making process in the task of preventing epidemics. By interpreting our demonstration results, policy implications were presented. Finally, some suggestions were made to comprehensively utilize the contact network to draw enhanced decision-support information.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8455-8460
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• 2014

Background: The National Central Cancer Registry of China (NCCR) affiliated to the Bureau of Disease Control, National Health and Family Planning Commission of China is responsible for cancer surveillance in the entire country. Cancer registration data from each local registry located in each province are collected by NCCR annually to be analyzed and published to provide useful information for policy makers and cancer researchers. Materials and Methods: Until 1st June, 2013, 219 population-based cancer registries submitted data of 2010 to the National Central Cancer Registry of China covering about 207,229,403 population, and 145 cancer registries were selected after quality evaluation for this study. Colorectal cancer cases were selected from the database according to ICD-10 coded as "C18-C20". We calculated the crude incidence and mortality rates by sex, age groups and location (urban/rural). The China population in 2000 and Segi's population were used as standardized populations for the calculation of age-standardized rates. The 6th National Population Census data of China was used to combined with the cancer registries' data to estimate the colorectal cancer burden in China in 2010. Results: Colorectal cancer was the sixth most common cancer in China. It was estimated that there were 274,841 new cases diagnosed in 2010 (157,355 in males and 117,486 in females), with the crude incidence rate of 20.1/100,000, highest in males in urban areas. Age-standardized rates by China standard population of 2000 (ASRcn) and World standard population (Segi's population, ASRwld) for incidence were 16.1/100,000 and 15.9/100,000 respectively. There were 132,110 cases estimated to have died from colorectal cancer in China in 2010 (76,646 men and 55,464 women) with the crude mortality rate of 10.1/100,000. The ASRcn and ASRwld for mortality were 7.55/100,000 and 7.44/100,000 respectively, higher in males and urban areas than in females and rural areas. The incidence and mortality rates increased with age, reaching peaksin the 80-84 year old, and oldest age groups, respectively. Conclusions: Colorectal cancer is one of the most common incident cancers and cause of cancer death in China. Primary and secondary prevention, with attention to a health lifestyle, physical activity and screening should be enhanced in the general population.