• Journal of Information Processing Systems
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• v.10 no.2
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• pp.300-313
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• 2014

Various Time Synchronization protocols for a Wireless Sensor Network (WSN) have been developed since time synchronization is important in many time-critical WSN applications. Aside from synchronization accuracy, energy constraint should also be considered seriously for time synchronization protocols in WSNs, which typically have limited power environments. This paper performs analysis of prominent WSN time synchronization protocols in terms of power consumption and test by simulation. In the analysis and simulation tests, each protocol shows different performance in terms of power consumption. This result is helpful in choosing or developing an appropriate time synchronization protocol that meets the requirements of synchronization accuracy and power consumption (or network lifetime) for a specific WSN application.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.17-27
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• 2021

Non-abelian group based cryptosystems are a latest research inspiration, since they offer better security due to their non-abelian properties. In this paper, we propose a novel approach to non-abelian group based public-key cryptographic protocols using semidirect products of finite groups. An intractable problem of determining automorphisms and generating elements of a group is introduced as the underlying mathematical problem for the suggested protocols. Then, we show that the difficult problem of determining paths and cycles of Cayley graphs including Hamiltonian paths and cycles could be reduced to this intractable problem. The applicability of Hamiltonian paths, and in fact any random path in Cayley graphs in the above cryptographic schemes and an application of the same concept to two previous cryptographic protocols based on a Generalized Discrete Logarithm Problem is discussed. Moreover, an alternative method of improving the security is also presented.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.4
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• pp.71-82
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• 2005

Though there are many authentication protocols for RFID system, only a few protocols support location privacy. Because of tag's hardware limitation, these protocols suffer from many security threats, especially from DoS (Denial of Service) attack. In this paper, we explain location privacy problem and show vulnerabilities of RFID authentication protocols. And then, we suggest an authentication protocol that is strong against location tracing, spoofing attack and DoS attack

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.5
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• pp.105-114
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• 2005

There are several goals or properties which authentication protocols may have; some of them are key freshness, far-end aliveness, key confirmation, etc. Most of them have extensively been discussed and studied so far in the literature. 'Responsibility' and 'credit', which were first raised by Abadi as additional goals, received quite an exceptional treatment; there were little response from researchers about these new goals. It is surprising to see that these two properties have slipped through any investigation, successfully achieving the positions as the goals for authentication protocols. In this paper, we investigate these two new properties and their relations to authentication protocols, and answers to the question: what brings us credit and responsibility.

• Fourth Industrial Review
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• v.2 no.2
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• pp.25-37
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• 2022

Purpose - The purposes of this research are: (1) Building and testing a research model that integrates Theory of Reasoned Action (TRA) with fear, perceived risk, and health protocols; (2) Examining the impact of compliance with health protocols on consumer behavior when offline shopping. Research design, data, and methodology - The data collection uses the self-administered survey method, and the questionnaire is distributed online. A total of 504 Indonesian population aged 18 years old or more participate in this research. Data are analyzed using factor analysis, multiple regression, and multiple regression with interaction. Result - This study reveals several findings: (1) Attitude and subjective norm have a significant effect on offline shopping behavior; (2) fear has a direct and indirect effect on offline shopping behavior; (3) the effect of perceived risk on the intensity of offline shopping is determined by compliance with health protocols. Conclusion - This paper discusses the direct influence of attitudes and subjective norms on behavior. This research also integrates fear, perceived risk, and health protocol factors in TRA, which may not have been done much, especially in the COVID-19 pandemic context.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.842-845
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• 2009

Wireless ad hoc networks often suffer from rapidly degrading performance with the number of user increases in the network. One of the major reasons for this rapid degradation of performance is the fact that users are sharing a single channel. Obviously, the problem of using single shared channel schemes is that the probability of collision increases with the number of nodes. Fortunately, it is possible to solve this problem with multi-channel approaches. Due to the especial properties of multiple channels, using the multiple channels is more efficient than single channel because it enhances the capacity of the channel and reduces the error rate during data transmission. Some multi-channel schemes us one dedicated channel for control packets and one separate channel for data transmissions. On the other hand, another protocols use more than two channels for data transmissions. This paper summarizes six multiple channel protocols based on these two kinds of schemes. Then we compare them and discuss the research challenge of multiple channel protocols.

• International journal of advanced smart convergence
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• v.12 no.1
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• pp.9-17
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• 2023

Recently, IoT technology has been widely used in many industries. Also research on integrating IoT technology with IoT sensors is actively underway. One of the important challenges in IoT is to support low-latency communication. With the development of communication networks and protocols, a variety of protocols are being used, and their performance is improving. In this paper, we compare the performance and analyze the characteristics of some of the major communication protocols in IoT application, namely MQTT, HTTP, and HTTPS. IoT sensors acquired data by connecting an Arduino equipped with ESP8266 and a temperature and humidity sensor (DHT11). The server measured the performance by building servers for each protocol using AWS EC2. We analyzed the packets transmitted between the Arduino and the server during the data transmission. We measured the amount of data and transfer time. The measurement results showed that MQTT had the lowest data transmission time and data amount among the three protocols.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.451-463
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• 2000

In this paper, we design the radio data link protocols with QoS provisioning for mobile multimedia such as voice, data, and video in CDMA-based ATM networks, and analyze the performance of the data link protocols. To support mobile multimedia traffic, the required QoS parameters and the characteristics are analyzed, and wireless protocol stacks are proposed for integrating the wireless access network and ATM transport networks, and radio data link protocols are designed for provisioning QoS Control. The data link protocols are analyzed assuming that the system is supporting voice and data traffic simultaneously. In case of data traffic, the delay and throughput of SREJ ARQ and Type-1 Hybrid ARQ scheme are compared, and in case of voice traffic, the packet loss rate of BCH coding is analyzed according to the varying data traffic loads. The results indicate that the adaptive radio link protocols are efficient to support QoS requirements while the complexities are increased.

• Imaging Science in Dentistry
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• v.47 no.1
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• pp.17-24
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• 2017

Purpose: The purpose of this study was to assess the accuracy, sensitivity, and specificity of the diagnosis of incipient furcation involvement with periapical radiography (PR) and 2 cone-beam computed tomography (CBCT) imaging protocols, and to test metal artifact interference. Materials and Methods: Mandibular second molars in 10 macerated pig mandibles were divided into those that showed no furcation involvement and those with lesions in the furcation area. Exams using PR and 2 different CBCT imaging protocols were performed with and without a metallic post. Each image was analyzed twice by 2 observers who rated the absence or presence of furcation involvement according to a 5-point scale. Receiver operating characteristic (ROC) curves were used to evaluate the accuracy, sensitivity, and specificity of the observations. Results: The accuracy of the CBCT imaging protocols ranged from 67.5% to 82.5% in the images obtained with a metallic post and from 72.5% to 80% in those without a metallic post. The accuracy of PR ranged from 37.5% to 55% in the images with a metallic post and from 42.5% to 62.5% in those without a metallic post. The area under the ROC curve values for the CBCT imaging protocols ranged from 0.813 to 0.802, and for PR ranged from 0.503 to 0.448. Conclusion: Both CBCT imaging protocols showed higher accuracy, sensitivity, and specificity than PR in the detection of incipient furcation involvement. Based on these results, CBCT may be considered a reliable tool for detecting incipient furcation involvement following a clinical periodontal exam, even in the presence of a metallic post.

• Progress in Medical Physics
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• v.14 no.1
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• pp.20-27
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• 2003

For the treatment of cancer using computer controlled linear accelerator, it is important to ensure that all equipments are operated properly. Therefore, many studies were performed and published on the safe use of radiotherapy machine controlled by computer logic and microprocessor These studies provided methods of preventing accident from software and hardware failure. In Korea, the use of computer controlled linear accelerator has increased over the past 10 years. However, there are no standard protocols for quality assurance (QA) of linear accelerator. In this study, three QA protocols from America, Japan, and Europe were collected and summarized. In addition, agreement and disagreement among the protocols were analyzed. In conclusion, the QA items included in the protocols were similar among the various QA protocols although there were differences in performance frequencies.