• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.6
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• pp.1231-1242
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• 2012

Traitor tracing schemes deter traitors from sharing their private keys by tracing at least one of the subscribers who were implicated in the construction of a pirate decoder. In general, it is assumed that the system manager in the scheme generates and distributes the subscribers' private key. But if the system manager knows the subscribers' private keys, he cannot convince a third party of a certain subscriber's piracy. To solve this problem, the system manager should not know the whole parts of subscribers' private keys and this leads to researches of asymmetric schemes. Moreover for the purpose of enhancing subscribers' privacy, there were two proposals of introducing anonymity onto asymmetric traitor tracing schemes, but one of them turned out to be a failure. In this paper, we point out that the other proposal also has flaws. We consider how to introduce anonymity to traitor tracing schemes, as a result, we suggest a new framework which is practical. We also construct a scheme by using an anonymous credential system and an asymmetric traitor tracing scheme. We prove the security of our scheme and consider the typical applications.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.75-87
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• 2010

Secure communication has been one of the main challenges in vehicular ad hoc networks(VANET) since broadcast messages from nearby vehicles contain life-critical information for drivers and passengers. So far various secure communication schemes have been proposed to secure the communication in VANET, and they satisfy most security requirements. However most of them need to put trust on roadside units(RSUs), which are usually deployed in unattended area and vulnerable to compromise. In this paper, we propose a secure communication scheme, which does not need to put trust on RSUs. And we adopt a grouping technique to averagely divide the huge burden in the server without jeopardizing the anonymity of users. Moreover we design a complete set of protocols to satisfy common security requirements with a relatively lower hardware requirement. At last, we evaluate the scheme with respect to security requirements, communication overhead, storage overhead and network performance.

• The Research Journal of the Costume Culture
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• v.28 no.6
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• pp.719-737
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• 2020

Live-streaming commerce business is growing as the consumption of video content and Smartphone shopping increases. This study examines the following three aspects: whether para-social interaction influences perceived interactivity; whether seller trust affects satisfaction with the experience; whether relationships are controlled by a moderated mediator of self-image congruity. An online survey was conducted with 203 women aged 20-30 years. They were asked to respond to the survey after watching a beauty category live-streaming commerce broadcast. The results revealed that the para-social interaction had a significant effect on perceived interactivity, seller trust and satisfaction with the experience. The findings also indicated that the perceived interactivity and seller trust mediated the relationship between para-social interaction and satisfaction with the experience. Regarding the mediated moderation effect of self-image congruity, it was statistically significant between para-social interaction and perceived interactivity through seller trust. A higher level of consumer's self-image congruity influenced the greater effect of para-social interaction on live commerce experience. This study makes important theoretical contributions to the para-social interaction in mobile commerce industry by emphasizing the mediating role of perceived interactivity and seller trust. This is achieved by examining the moderating effects of self-congruity on satisfaction with the experience. The results also verify the seller's crucial role in live-streaming commerce market which leads to the consumers greater fulfillment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.10
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• pp.1312-1318
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• 2020

In this paper, we propose a video transmission scheme for exclusive OR based video streaming (XC) that can improve the efficiency of video streaming by using receivers' caches and coding of video data. Contrary to conventional streaming schemes such as multicast where video contents can be transmitted on single channel only when two clients request the same video, the proposed streaming scheme can transmit video contents on single channel conditionally according to the status of the clients' caches even though two clients request different video contents. We analyze the performance of the proposed transmission for XC in terms of the streaming efficiency through extensive computer simulations and compare it with a conventional scheme. Simulation results show that the proposed scheme can enhance the streaming efficiency by 21%, compared with the conventional scheme.

• Journal of Preventive Medicine and Public Health
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• v.54 no.2
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• pp.119-128
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• 2021

Objectives: Ongoing, proactive, planned, and patient-centered diabetes education is the cornerstone of care for all persons with diabetes. Thus, the aim of this study was to explore the information needs of type 2 diabetes mellitus patients receiving insulin treatment in North-East Ethiopia. Methods: The study was conducted from July 2019 to January 2020 using a qualitative enquiry (phenomenological approach) with purposive sampling. Face-to-face in-depth interviews were used to collect data until reaching theoretical saturation. The participants were type 2 diabetes patients receiving insulin treatment. They were identified from the diabetes patients' registration book at the diabetes clinic and interviewed at their appointment time, and were selected to include wide variations in terms of socio-demographic characteristics. Twenty-four participants (11 men and 13 women), with a median age of 57 years, were interviewed. The data were organized using QDA Miner Lite version 2.0.7 and analyzed thematically using narrative strategies. Results: Most participants had not heard of diabetes before their diagnosis. They had limited knowledge of diabetes, but ascribed different connotations for it in the local language (Amharic). The needs reflections of patients were categorized into diabetes education and participants' recommendations. Diabetes education was totally absent at hospitals, and patients received education primarily from the Ethiopian Diabetes Association and broadcast and digital media. Thus, the major concern of patients was the availability of diabetes education programs at health institutions. Conclusions: Patients' main concern was the absence of routine diabetes education, which necessitates urgent action to implement diabetes education programs, especially at health institutions.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.527-532
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• 2020

Seoul terminal maneuvering area (TMA) that includes Incheon International Airport (ICN) and Gimpo International Airport is a very congested airspace with around 1,000 daily flights and the airspace blocked at the boundary between Incheon flight information region (FIR) and Pyongyang FIR. Consequently, with frequency radar vectorings, separation assurance in this airspace is complicated thus resulting in higher controller workload. In this paper, the conflict and collision risks in Seoul TMA are analyzed using recorded ADS-B data for past three years. Using the recorded trajectories, original flight plan procesures and routes are reconstructed and the risks are quantified using detect and avoid well clear (DWC) metric that is developed for large unmanned aircraft system. The region west of ICN was found to be the highest risk area regardless of the runway directions. In addition, merge and crossing points between procedures displayed relatively high risks.

• Journal of East-Asian Urban History
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• v.2 no.1
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• pp.113-128
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• 2020

Right before the outbreak of the War of Resistance Against Japanese Aggression (1937-1954), the Great Eastern Broadcasting Station (GEBS) was established in Shanghai under the aegis of the Ministry of Foreign Affairs of Japan (MOFA). Prior to the launching of the GEBS, Japan had not owned similar radio stations in China for years. As a result, the Embassy of Japan in China held rounds of discussions on the plan and Japanese governments, ranging from the MOFA, the Navy, the Army, the Ministry of Communications (MOC), and NHK-Japan Broadcasting Corporation (Nihon Hoso Kyoku) provided financial, technological, and equipment support. In the mid-1930s when the Sino-Japanese relations became intensified, the GEBS assumed the primary role of disseminating government policies to over 30,000 Japanese expatriates in Shanghai to make sure that they could remain settled while supporting military endeavors of the Japanese army once the war between China and Japanese broke out. After 1937, the GEBS became an essential propaganda tool to advance imperial policies of Japan. Although the station differed from the Army-controlled Greater Shanghai Broadcasting Station (Dai Shanhai Hoso Kyoku) in many aspects, it was in line with the latter in terms of advancing wartime ideology of the Japanese empire. As the Japanese-occupied areas were enlarged, target audience of the GEBS also expanded to Chinese people and foreign nationals when Japanese, English, Russian, and Shanghai-dialect news was broadcast by the station. Suffice it to say that the GEBS was closely related to wartime propaganda of the Japanese imperial expansion.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.67-74
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• 2022

To analyze the motion of aircraft through computing the dynamics equations, true airspeed is essential for obtaining aerodynamic loads. Although the airspeed is measured by on-board instruments such as pitot tubes, measurement data are difficult to obtain for commercial flights because they include sensitive data about the airline operations. One of the commonly available trajectory data, Automatic Dependent Surveillance-Broadcast data, provide aircraft's speed in the form of ground speed. The ground speed is a vector sum of the local wind velocity and the true airspeed. This paper present a method to estimate true airspeed by combining the trajectory, meteorological, and topology data available to the public. To integrate each data, we first matched the coordinate system and then unified the altitude reference to the mean sea level. We calculated the wind vector for all trajectory points by interpolating from the lower resolution grid of the meteorological data. Finally, we calculate the true airspeed from the ground speed and the wind vector. These processes were applied to several sample trajectories with corresponding meteorological data and the topology data, and the estimated true airspeeds are presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.2
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• pp.445-466
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• 2022

As everything linking to the internet, people can subscribe to various services from a service provider to facilitate their lives through the Internet of Things (IoT). An obligatory thing for the service provider is that they should push the service data safely and timely to multiple IoT terminal devices regularly after the IoT devices accomplishing the service subscription. In order to control the service message received by the legal devices as while as keep the confidentiality of the data, the public key encryption algorithm is utilized. While the existing public encryption algorithms for push service are too complicated for IoT devices, and almost of the current subscription schemes based on push mode are relying on centralized organization which may suffer from centralized entity corruption or single point of failure. To address these issues, we design a secure subscription-push service scheme based on blockchain and edge computing in this article, which is decentralized with secure architecture for the subscription and push of service. Furthermore, inspired by broadcast encryption and multicast encryption, a new encryption algorithm is designed to manage the permissions of IoT devices together with smart contract, and to protect the confidentiality of push messages, which is suitable for IoT devices. The edge computing nodes, in the new system architecture, maintain the blockchain to ensure the impartiality and traceability of service subscriptions and push messages, meanwhile undertake some calculations for IoT devices with limited computing power. The legalities of subscription services are guaranteed by verifying subscription tags on the smart contract. Lastly, the analysis indicates that the scheme is reliable, and the proposed encryption algorithm is safe and efficient.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.119-124
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• 2022

The international gnss service (IGS) provides real-time service (RTS) orbit and clock correction applicable to the broadcast ephemeris of GNSS satellites. However, since the RTS correction cannot be received if the Internet connection is lost, the RTS correction should be predicted and used when a signal interruption occurs in order to perform stable precise point positioning (PPP). In this paper, PPP was performed by predicting orbit and clock correction using a long short-term memory (LSTM) algorithm in real-time during the signal loss. The prediction performance was analyzed by implementing the LSTM algorithm in RPI (raspberry pi), the processing speed of which is not high. Compared to the polynomial prediction model, LSTM showed excellent performance in long-term prediction.