• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.377-387
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• 2009

Digital signatures not only provide a way of guaranteeing the integrity of data but also establish the identity of the signer. However, basic digital signature format which contains only the signature of the signer does not guarantee the correctness of its creation time, and it can not remain valid over long periods. This paper proposes a system which integrates timestamp service into digital signatures. The system provides online services for the creation and verification of long term digital signatures which can give the guarantee of the correctness of their creation times and can be proved to be valid over long periods. The proposed system can be used in the various areas such as e-commerce contracts, document archival services, and invoice applications, which requires long term digital signatures. The proposed system is tested with the KRISS timestamp service system.

• Journal of the Korea Computer Industry Society
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• v.2 no.11
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• pp.1395-1406
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• 2001

In order to cover a widespread service range, terrestrial/satellite-mixed network is being combined with terrestrial ATM network. This dissertation analyzes and investigates several previously existent CDV compensation methods in order to compensate CDV arising from interfacing satellite TDMA and ATM. Specifically to supplement the problems of timestamp and cell number counting methods, new Variable Timestamp method for CDV compensation is proposed. To evaluate the proposed method, MMPP(Markov Modulated Poisson Process), which can express VBR service very well, is selected as a cell input traffic model of terrestrial transmitting earth station. After several simulation, it is also confirmed that CDV compensation capability for VBR services is very superior to the cell number counting method. In this case, as the timestamp number Nts increases, CDV compensation capability increases, and the CDV distribution length is reduced.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.75-84
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• 2018

In this research, a bit correction technique of data hiding method in timestamp of MFT entry in NTFS file system is proposed. This method is proposed in two ways, depending on the number of bytes of data to hide. A basic data hiding method using a bit correction technique to solve the problems of the conventional 2-byte technique is proposed. In order to increase the capacity of the data, a 3-byte data hiding method using an extended bit correction technique is proposed. The data hiding method in the timestamps is based on the fact that is not revealed in the Windows explorer window and the command prompt window even if any data is hidden in the timestamp area of less than one second. It is shown that the validity of the proposed method through the experimental two cases of the basic data hiding method by the bit correction method and the 3-byte data hiding method by the extended bit correction method.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.5
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• pp.439-444
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• 2016

This paper proposes the technique to protect the privacy of those who uses Smart Tourism Service based on location. The proposed privacy protection technique (1) generates a shared private key, OTK(One Time Key) without information exchanging Users with a Tourism Server and provides Users and a Tourism Server with message confidentiality by encrypting data with the key, (2) concatenates users' ID, login time(timestamp), and randomly-generated nonce, generates OTK by hashing with a hash function, encrypts users' location information and query by using the operation of OTK and XOR and provides Users and a Tourism Server with message confidentiality by sending the encrypted result. (3) protects a message replay attack by adding OTK and timestamp. Therefore, this paper not only provides data confidentiality and users' privacy protection but also guarantees the safety of location information and behavior pattern data.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.596-610
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• 2012

This paper proposes a method to provide the high quality 3D broadcasting service in a mobile broadcasting system. In this method, audio and video data are delivered through a heterogeneous network, consisting of a mobile network as well as a broadcasting network, due to the limited bandwidth of the broadcasting system. However, it is more difficult to synchronize the left and right video frames of a 3D stereoscopic service, which come through different types of networks. The proposed method suggests the use of the offset from the initial timestamp of RTP (Real Time Protocol) to determine the order of frames and to find the pair of a left and a right frame that must be played at the same time. Additionally, a new signaling method is introduced for a mobile device to request a 3D service and to get the initial RTP timestamp.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.722-737
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• 2011

In this paper, we propose an estimation of network jitter that occurs when transmitting TCP packets containing MPEG-2 TS in progressive streaming service over wired or wireless Internet networks. Based on the estimated network jitter size, we can calculate required de-jitter buffering time to absorb the network jitter at the receiver side. For this purpose, by exploiting the PCR timestamp existing in the TS packet header, we create a new timestamp information that is marked in the optional field of TCP packet header to estimate the network jitter. By using the proposed de-jitter buffering scheme, it is possible to employ the conventional T-STD buffer model without any modification in the progressive streaming service over IP networks. The proposed method can be applicable to the recently developed international standard, MPEG DASH (dynamic adaptive streaming over HTTP) technology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.323-336
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• 2000

In order to achieve the deployment of B-ISDN services in a short time, B-ISDN is being combined with terrestrial ATM network and satellite network which covers a widespread service range. This paper analyzes and investigates several previously existent CDV compensation methods in order to compensate CDV arising from interfacing satellite TDMA and ATM. Specifically to supplement the problems of timestamp and cell number counting methods, new Partial Timestamp mechanism for CDV compensation is proposed. The CDV compensating efficiency of the proposed mechanism is analyzed and evaluated by simulations. It goes to show that Partial timestamps mechanism has many advantages in the aspect of the CDV compensation.

• Journal of Korea Multimedia Society
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• v.9 no.8
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• pp.1020-1029
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• 2006

Realization of high-capacity quality-of-service router needs fair packet schedulers with a lower complexity. Timestamp based fair packet schedulers have the ideal complexity of O(log V), where V is the maximum number of admitted flows, but it has been recently reduced to O(1) using bin concept. However, the latency property was deteriorated and the bandwidth utilization was also declined. In addition, traffic flows requiring strong delay bound may not be admitted. To overcome these problems, this paper proposes a Mini-Bin based Start-Time (MBST) scheduler with variable complexity and evaluates its performance. The MBST scheduler uses the timestamp calculation scheme of start-time based schedulers to enhance the bandwidth utilization and also introduces mini-bin concept to improve the latency, The performance evaluation shows that the proposed scheduler can reduce the complexity of the legacy start-tine based schedulers by $1.8{\sim}5$ times without deteriorating the bandwidth utilization property.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.203-210
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• 2006

Fair packet scheduling algorithms supporting quality-of-services of real-time multimedia applications can be classified into the following two design schemes in terms of the reference time used in calculating the timestamp of arriving packet: Finish-time Design (FD) and Start-time Design (SD) schemes. Since the former can adjust the latency of a flow with raising the flow's reserved rate, it has been applied to a router for the guaranteed service of the IETF (Internet Engineering Task Force) IntServ model. However, the FD scheme may incur severe bandwidth loss for traffic flows requiring low-rate but strong delay bound such as internet phone. In order to verify the usefulness of the SD scheme based router for the IETF guaranteed service, this paper analyzes and compares two design schemes in terms of bandwidth and payload utilizations. It is analytically proved that the SD scheme is better bandwidth utilization than the FD one, and the simulation result shows that the SD scheme gives better payload utilization by up to 20%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.6
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• pp.1545-1559
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• 2023

In the cloud environment, microservices are implemented through Kubernetes, and these services can be expanded or reduced through the autoscaling function under Kubernetes, depending on the service request or resource usage. However, the increase in the number of nodes or distributed microservices in Kubernetes and the unpredictable autoscaling function make it very difficult for system administrators to conduct operations. Artificial Intelligence for IT Operations (AIOps) supports resource management for cloud services through AI and has attracted attention as a solution to these problems. For example, after the AI model learns the metric or log data collected in the microservice units, failures can be inferred by predicting the resources in future data. However, it is difficult to construct data sets for generating learning models because many microservices used for autoscaling generate different metrics or logs in the same timestamp. In this study, we propose a cloud data refining module and structure that collects metric or log data in a microservice environment implemented by Kubernetes; and arranges it into computing resources corresponding to each service so that AI models can learn and analogize service-specific failures. We obtained Kubernetes-based AIOps learning data through this module, and after learning the built dataset through the AI model, we verified the prediction result through the differences between the obtained and actual data.