• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.7 s.349
• /
• pp.1-13
• /
• 2006

In this paper, we introduce a novel key management scheme that is based on the key pre-distribution but provides the key re-distribution method, in order to manage keys for message encryption and authentication of lower-layer sensor nodes on hierarchical mobile sensor networks. The characteristics of our key management are as follows: First, the role of key management is distributed to aggregator nodes as well as a sink node, to overcome the weakness of centralized management. Second, a sink node generates keys using regression model, thus it stores only the information for calculating the keys using the key information received from nodes, but does not store the relationship between a node and a key, and the keys themselves. As the disadvantage of existing key pre-distributions, they do not support the key re-distribution after the deployment of nodes, and it is hard to extend the key information in the case that sensor nodes in the network enlarge. Thirdly, our mechanism provides the resilience to node capture(${\lambda}$-security), also provided by the existing key pre-distributions, and fourth offers the key freshness through key re-distribution, key distribution to mobile nodes, and scalability to make up for the weak points in the existing key pre-distributions. Fifth, our mechanism does not fix the relationship between a node and a key, thus supports the anonymity and untraceability of mobile nodes. Lastly, we compare ours with existing mechanisms, and verify our performance through the overhead analysis of communication, computation, and memory.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.7
• /
• pp.841-850
• /
• 2019

The Korean government has designated speed-limit zones and speed limits in 19 ports and 3 routes to ensure safe navigation and transportation. However, the speed limit differs from port to port, no practical means of management exist. This often leads to violation of the speed limit. Additionally, ship collisions due to human error continue to occur. First, the study analyzed marine accidents that occurred at trade ports and fairways. The result of the analysis revealed the occurrence of 1344 accidents (average 269 cases per year) from 2014 to 2018. Five hundred sixty three accidents involved fishing boats, whereas, merchant vessels were involved in 508 cases. Second, the efficacy of the application of voice and message warnings to GPS plotters and electronic chart display and information system (ECDIS) was reviewed, and these were proposed as measures to inform vessel operators of the hazards of speed limit violation. Third, experts' opinions from relevant agencies and navigation system manufacturers were consulted and it was found that the proposed warning function was technically implementable. The findings are expected to help reduce human error among ship operators and establish a Korean e-navigation system.

• Journal of the Korea Society of Computer and Information
• /
• v.26 no.9
• /
• pp.89-96
• /
• 2021

In this paper, we analyzed that the user authentication scheme for TMIS(Telecare Medicine Information System) proposed by Al-Saggaf et al. In 2019, Al-Saggaf et al. proposed authentication scheme using biometric information, Al-Saggaf et al. claimed that their authentication scheme provides high security against various attacks along with very low computational cost. However in this paper after analyzing Al-Saggaf et al's authentication scheme, the Al-Saggaf et al's one are missing random number s from the DB to calculate the identity of the user from the server, and there is a design error in the authentication scheme due to the lack of delivery method. Al-Saggaf et al also claimed that their authentication scheme were safe against a variety of attacks, but were vulnerable to password guessing attack using login request messages and smart cards, session key exposure and insider attack. An attacker could also use a password to decrypt the stored user's biometric information by encrypting the DB with a password. Exposure of biometric information is a very serious breach of the user's privacy, which could allow an attacker to succeed in the user impersonation. Furthermore, Al-Saggaf et al's authentication schemes are vulnerable to identity guessing attack, which, unlike what they claimed, do not provide significant user anonymity in TMIS.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.19 no.3
• /
• pp.119-131
• /
• 2009

The world's widely used key exchange protocols are open cryptographic communication protocols, such as TLS/SSL, whereas in the financial field in Korea, key exchange protocols developed by industrial classification group have been used that are based on PKI(Public Key Infrastructure) which is suitable for the financial environments of Korea. However, the key exchange protocols are not only vulnerable to client impersonation attacks and known-key attacks, but also do not provide forward secrecy. Especially, an attacker with the private keys of the financial security server can easily get an old session-key that can decrypt the encrypted messages between the clients and the server. The exposure of the server's private keys by internal management problems, etc, results in a huge problem, such as exposure of a lot of private information and financial information of clients. In this paper, we analyze the weaknesses of the cryptographic communication protocols in use in Korea. We then propose two key exchange protocols which reduce the replacement cost of protocols and are also secure against client impersonation attacks and session-key and private key reveal attacks. The forward secrecy of the second protocol is reduced to the HDH(Hash Diffie-Hellman) problem.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.22 no.1
• /
• pp.43-56
• /
• 2012

Wireless sensor networks consist of numerous small-sized nodes equipped with limited computing power and storage as well as energy-limited disposable batteries. In this networks, nodes are deployed in a large given area and communicate with each other in short distances via wireless links. For energy efficient networks, dynamic clustering protocol is an effective technique to achieve prolonged network lifetime, scalability, and load balancing which are known as important requirements. this technique has a characteristic that sensing data which gathered by many nodes are aggregated by cluster head node. In the case of cluster head node is exposed by attacker, there is no guarantee of safe and stable network. Therefore, for secure communications in such a sensor network, it is important to be able to encrypt the messages transmitted by sensor nodes. Especially, cluster based sensor networks that are designed for energy efficient, strongly recommended suitable key management and authentication methods to guarantee optimal stability. To achieve secured network, we propose a key management scheme which is appropriate for hierarchical sensor networks. Proposed scheme is based on polynomial key pool pre-distribution scheme, and sustain a stable network through key authentication process.

• The Journal of Korean Association of Computer Education
• /
• v.11 no.1
• /
• pp.57-64
• /
• 2008

This paper presents a web-based virtual educational system for Java language, which consists of a management system named Java Web Player (JWP) and creative multimedia contents for the lectures of Java language. The JWP is a Java application program free from security problems by the Java Web Start technologies that supports an integrated learning environment including three important learning procedures: Java concept learning process, programming practice process and assessment process. On-line voice presentation and its related texts together with moving images are synchronized for efficiently conveying creative contents to learners. Furthermore, a simple and useful compiler is included in the JWP for providing user-friendly language practice environment enabling such as coding, editing, executing, and debugging Java source files on the Web. Finally, simple multiple choices are given suddenly to the learners while they are studying through the JWP and the test results are displayed on the message box. In order to show the validity of the proposed virtual educational system we analysed and assessed the learners' academic performance on the five quizzes for one semester.

• Journal of KIISE:Databases
• /
• v.34 no.6
• /
• pp.528-545
• /
• 2007

Recently ontology has been an attractive technology along with the business strategy of providing a plenty of more intelligent services. The essential problem in application domains using ontology is that all members, agents, and application programs in the domains must share the same ontology concepts. However, a variety of mobile devices, sensing devices, and network components manufactured by various companies, a variety of common carriers, and a variety of contents providers make multiple heterogeneous ontologies more likely to coexist. We can see many past researches fallen into resolving this semantic interoperability. Such methods can be broadly classified into by-mapping, by-merging, and by-translation. In this research, we focus on by-translation among them which uses a translation rule directly made between two heterogeneous ontology data like OntoMorph. However, the manual composition of the direct translation rule is not convenient by itself and if there are N ontologies, the direct method has the rule composition complexity of $O(N^2)$ in the worst case. Therefore, in this paper we introduce the cascade composition of translation rules based on web openness in order to improve the complexity. The research result made us recognize some important factors in an ontology translation system, that is speediness of translation, and conveniency of translation rule composition, and some experiments and comparing analysis with existing methods showed that our cascade method has more conveniency with insuring the speediness and the correctness.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.47 no.1
• /
• pp.128-138
• /
• 2010

In this paper, we propose a new bit assignment scheme for Wyner-Ziv video coding. Distributed video coding (DVC) is a new video coding paradigm which enables greatly low complexity encoding because it does not have any motion prediction module at encoder. Therefore, it is very well suited for many applications such as video communication, video surveillance, extremely low power consumption video coding, and other portable applications. Theoretically, the Wyner-Ziv video coding is proved to achieve the same rate-distortion (RD) performance comparable to that of the joint video coding. However, its RD performance has much gap compared to MC-DCT-based video coding such as H.264/AVC. Moreover, Transform Domain Wyner-Ziv (TDWZ) video coding which is a kind of DVC with transform module has difficulty of exact bit assignment because the entire image is treated as a same message. In this paper, we propose a feasible bit assignment algorithm using adaptive quantization matrix selection for the TDWZ video coding. The proposed method can calculate suitable bit amount for each region using the local characteristics of image. Simulation results show that the proposed method can enhance coding performance.

• Journal of the Korea Society for Simulation
• /
• v.20 no.4
• /
• pp.81-89
• /
• 2011

Underwater wireless network can be useful in various fields such as underwater environment observation, catastrophe prevention, ocean resources exploration, ocean organism research, and vessel sinking exploration. We need to develop an efficient design for Medium Access Control (MAC) protocol to improve multiple data communication in underwater environment. Aloha protocol is one of the basic and simple protocols, but it has disadvantage such as collision occurs oftenly in communication. If there is collision occured in RF communication, problem can be solved by re-sending the data, but using low frequency in underwater, the re-transmission has difficulties due to slow bit-rate. So, Time Division Multiple Access (TDMA) based MAC protocol is going to be used to avoid collisions, but if there is no data to send in existing TDMA, time slot should not be used. Therefore, this paper proposes dynamic TDMA protocol mechanism with reducing the time slots by sending short "I Have No Data" (IHND) message, if there is no data to transmit. Also, this paper presents mathematic analysis model in relation to data throughput, channel efficiency and verifies performance superiority by comparing the existing TDMA protocols.

• Journal of Korean Philosophical Society
• /
• v.131
• /
• pp.77-103
• /
• 2014

It is well known that Nietzsche insists on the affirmation of life, and the subject of 'affirmation of life' is a familiar one in Nietzsche literature. We want to throw an unfamiliar light on this familiar subject, connecting the theme of affirmation with that of redemption, and insisting on the centrality of the theme of redemption in Zarathustra's teaching of ${\ddot{U}}bermensch$. For Nietzsche, the redemption of human life means that its life is endowed with some meaning and its existence is positively justified. With this redemption, an active affirmation of life is possible, which means that we not only endure this life once but also request it for indefinite times. According to Nietzsche, for this kind of redemption and active affirmation we need an ultimate ground of meaning and only the excellence of life, that is, of 'will to power' can serve as this ultimate ground. Accepting the Greek way of identifying virtue with excellence, Nietzsche thought that life can justify itself at the ultimate form of life in ${\ddot{U}}bermensch$. Then, through ${\ddot{U}}bermensch$ the way is opened for man to endow meanings on and justify its life. That is, ${\ddot{U}}bermensch$ is not only the one who affirms its life, but also the very condition in which humanity can justify its life in general. With the goal and ideal of ${\ddot{U}}bermensch$ accepted, the affirmation and redemption of an individual life depends on how it manages to create its own life in relation to this goal and ideal. According to Nietzsche, though we cannot go back to the past, we still can recreate it and change its meanings through working on the future. Only those who try to create a meaningful future and thus recreate the past could redeem and affirm their own lives. That is, for Nietzsche, to affirm and redeem one's life means not just to change one's attitude to life but to create and recreate it with the eye for ${\ddot{U}}bermensch$.