• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.71-72
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• 2015

WSN의 센서 노드는 제한된 자원으로 인해 보안상의 취약성을 가지며 공격자는 쉽게 임의의 데이터를 삽입하는 허위 데이터 주입 공격을 할 수 있다. WSN에서는 이러한 공격이 치명적이기 때문에 허위 데이터를 가능한 빨리 여과해야 한다. 허위 데이터 주입 공격을 탐지하는 기법으로 동적 여과 기법이 제안되었는데 이 기법은 초기 분배된 비밀키에 대한 재분배가 이루어지지 않아 같은 공격에 계속 노출될 경우 불필요한 에너지 소모가 발생한다. 본 논문에서 제안하는 기법은 효율적인 키 재분배를 통해 허위 데이터를 빨리 감지하고 에너지 효율성을 향상시킨다. 전달 노드에서 허위 데이터가 탐지되면 정의된 알람 메시지를 통해 베이스 스테이션에 보고되고 키 재분배를 수행하여 더 효율적으로 허위 데이터를 감지한다. 그러므로 제안 기법은 기존 기법과 비교하였을 때 허위 데이터를 조기에 감지하고 전체 네트워크의 에너지를 절약한다.

• Journal of the Korea Society of Computer and Information
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• v.18 no.11
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• pp.115-124
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• 2013

In this paper, we suggest a secure data dissemination by Lightweight Individual Encryption Multicast scheme over wireless sensor networks using the individual encryption method with Forward Error Correction instead of the group key encryption method. In wireless sensor networks, a sink node disseminates multicast data to the number of sensor nodes to update the up to date software such as network re-programming and here the group key encryption method is the general approach to provide a secure transmission. This group key encryption approach involves re-key management to provide a strong secure content distribution, however it is complicated to provide group key management services in wireless sensor networks due to limited resources of computing, storage, and communication. Although it is possible to control an individual node, the cost problem about individual encryption comes up and the individual encryption method is difficult to apply in multicast data transmission on wireless sensor networks. Therefore we only use 0.16% of individually encrypted packets to securely transmit data with the unicast to every node and the rest 99.84% non-encrypted encoded packets is transmitted with the multicast for network performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3465-3479
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• 2017

Information-Centric Vehicular Ad Hoc Network (IC-VANET) is a promising network architecture for the future intelligent transport system. Video streaming applications over IC-VANET not only enrich infotainment services, but also provide the drivers and pedestrians real-time visual information to make proper decisions. However, due to the characteristics of wireless link and frequent change of the network topology, the packet loss seriously affects the quality of video streaming applications. In this paper, we propose a REceiver-Driven loss reCOvery Mechanism (REDCOM) to enhance video dissemination over IC-VANET. A Markov chain based estimation model is introduced to capture the real-time network condition. Based on the estimation result, the proposed REDCOM recovers the lost packets by requesting additional forward error correction packets. The REDCOM follows the receiver-driven model of IC-VANET and does not require the infrastructure support to efficiently overcome packet losses. Experimental results demonstrate that the proposed REDCOM improves video quality under various network conditions.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.2
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• pp.113-119
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• 2016

Wireless sensor networks are vulnerable to an adversary due to scarce resources and wireless communication. An adversary can compromise a sensor node and launch a variety of attacks such as false report injection attacks. This attack may cause monetary damage resulting in energy drain by forwarding the false reports and false alarms at the base station. In order to address this problem, a number of en-route filtering schemes has been proposed. Notably, a dynamic en-route filtering scheme can save energy by filtering of the false report. In the key dissemination phase of the existing scheme, the nodes closer to the source node may not have matching keys to detect the false report. Therefore, continuous attacks may result in unnecessary energy wastage. In this paper, we propose a key re-distribution scheme to solve this issue. The proposed scheme early detects the false report injection attacks using initially assigned secret keys in the phase of the key pre-distribution. The experimental results demonstrate the validity of our scheme with energy efficiency of up to 26.63% and filtering capacity up to 15.92% as compared to the existing scheme.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3123-3129
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• 2016

Background: Cancer is the fourth leading cause of death in Sabah Malaysia with a reported age-standardized incidence rate was 104.9 per 100,000 in 2007. The incidence rate depends on non-mandatory notification in the registry. Under-reporting will provide the false picture of cancer control program effectiveness. The present study was to evaluate the performance of the cancer registry system in terms of representativeness, data quality, simplicity, acceptability and timeliness and provision of recommendations for improvement. Materials and Methods: The evaluation was conducted among key informants in the National Cancer Registry (NCR) and reporting facilities from Feb-May 2012 and was based on US CDC guidelines. Representativeness was assessed by matching cancer case in the Health Information System (HIS) and state pathology records with those in NCR. Data quality was measured through case finding and re-abstracting of medical records by independent auditors. The re-abstracting portion comprised 15 data items. Self-administered questionnaires were used to assess simplicity and acceptability. Timeliness was measured from date of diagnosis to date of notification received and data dissemination. Results: Of 4613 cancer cases reported in HIS, 83.3% were matched with cancer registry. In the state pathology centre, 99.8% was notified to registry. Duplication of notification was 3%. Data completeness calculated for 104 samples was 63.4%. Registrars perceived simplicity in coding diagnosis as moderate. Notification process was moderately acceptable. Median duration of interval 1 was 5.7 months. Conclusions: The performances of registry's attributes are fairly positive in terms of simplicity, case reporting sensitivity, and predictive value positive. It is moderately acceptable, data completeness and inflexible. The usefulness of registry is the area of concern to achieve registry objectives. Timeliness of reporting is within international standard, whereas timeliness to data dissemination was longer up to 4 years. Integration between existing HIS and national registration department will improve data quality.

• Journal of Korean Society of Transportation
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• v.29 no.5
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• pp.121-138
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• 2011

More affordable and available cutting-edge technologies (e.g., wireless vehicle communication) are regarded as a possible alternative to the fixed infrastructure-based traffic information system requiring the expensive infrastructure investments and mostly implemented in the uninterrupted freeway network with limited spatial system expansion. This paper develops an advanced decentralized traveler information System (ATIS) using vehicle-to-vehicle (V2V) communication system whose performance (drivers' travel time savings) are enhanced by three complementary functions (autonomous automatic incident detection algorithm, reliable sample size function, and driver behavior model) and evaluates it in the typical $6{\times}6$ urban grid network with non-recurrent traffic state (traffic incident) with the varying key parameters (traffic flow, communication radio range, and penetration ratio), employing the off-the-shelf microscopic simulation model (VISSIM) under the ideal vehicle communication environment. Simulation outputs indicate that as the three key parameters are increased more participating vehicles are involved for traffic data propagation in the less communication groups at the faster data dissemination speed. Also, participating vehicles saved their travel time by dynamically updating the up-to-date traffic states and searching for the new route. Focusing on the travel time difference of (instant) re-routing vehicles, lower traffic flow cases saved more time than higher traffic flow ones. This is because a relatively small number of vehicles in 300vph case re-route during the most system-efficient time period (the early time of the traffic incident) but more vehicles in 514vph case re-route during less system-efficient time period, even after the incident is resolved. Also, normally re-routings on the network-entering links saved more travel time than any other places inside the network except the case where the direct effect of traffic incident triggers vehicle re-routings during the effective incident time period and the location and direction of the incident link determines the spatial distribution of re-routing vehicles.