• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3328-3349
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• 2020

With rapid development of ubiquitous computing and location-based services (LBSs), human trajectory data and associated activities are increasingly easily recorded. Inappropriately publishing trajectory data may leak users' privacy. Therefore, we study publishing trajectory data while preserving privacy, denoted privacy-preserving activity trajectories publishing (PPATP). We propose S-PPATP to solve this problem. S-PPATP comprises three steps: modeling, algorithm design and algorithm adjustment. During modeling, two user models describe users' behaviors: one based on a Markov chain and the other based on the hidden Markov model. We assume a potential adversary who intends to infer users' privacy, defined as a set of sensitive information. An adversary model is then proposed to define the adversary's background knowledge and inference method. Additionally, privacy requirements and a data quality metric are defined for assessment. During algorithm design, we propose two publishing algorithms corresponding to the user models and prove that both algorithms satisfy the privacy requirement. Then, we perform a comparative analysis on utility, efficiency and speedup techniques. Finally, we evaluate our algorithms through experiments on several datasets. The experiment results verify that our proposed algorithms preserve users' privay. We also test utility and discuss the privacy-utility tradeoff that real-world data publishers may face.

• Informatization Policy
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• v.24 no.2
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• pp.20-42
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• 2017

In this paper, we focus on classification of security threats and definitions of security requirements for Internet banking service. Threats are classified based on the past and potential incidents, based upon which we will be able to propose security requirements. In order to identify security threats, the structure of the Internet banking service is classified into three sections - the financial institutions, the network, and the user-terminal - and we defined arising threats for each section. We focused the analysis especially on the user-terminal section, which is relatively vulnerable, causing difficulties in securing stability of the service as a whole. The analyzed security threats are expected to serve the foundation for safe configuration of various Internet banking services.

• Spatial Information Research
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• v.4 no.2
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• pp.181-187
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• 1996

The purposes of this paper is to propose a methology for the efficient work analysis and system configuration for the developing of facilities information management system for city gas facilites. For this, work defining and user requirement was reflected on system, and systematic system development was derived through defining the problems of existing facilities management system. The study can be summarized as follows: First, existing work was computerized effectively by feedback with user interview on analyzing work. Second, it is appropriate to approach on system development in view of SI(System Integrate) which integrates Management Information System(MIS) and Geograph¬ic Information System(GIS). Third, it was found that Client-Server environment is good solution for now and future computer environment.

• Convergence Security Journal
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• v.8 no.4
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• pp.121-126
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• 2008

It is of great practical interest to decide when to stop testing a software system in development phase and transfer it to the user. This decision problem called an optimal release policies. In this paper discussed to specify an optimal release policies. In this paper, propose an optimal release policies of the life distribution applied Erlang distribution of special pattern of Gamma distribution. In this paper, discuss optimal software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement. From Sensitivity Analysis, make out estimating software optimal release time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.269-276
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• 2008

In this paper, we analyze the M-WiMAX UL capacity limits under 2-Tier cell layout, considering the effects of random user position, path loss models, fading channel and adjacent channel interference from WCDMA system. In order to make the analysis approximate to the practical system capacity, we propose a MCS-based capacity analysis method considering the effects of PER requirement and the utilized MCS levels in M-WiMAX system. The proposed MCS-based method is validated through a system-level Monte Carlo simulation. Furthermore, a comparison between the conventional Shannon method and the proposed MCS-based method is presented and the optimum cell radius is suggested.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.88-96
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• 2001

Future mobile communication networks, which consist of ATM-based B-ISDN backbone networks and wireless ATM networks, will provide u user with broadband connection and QoS service. These network systems need the lossless handoff methods which support user mobility, satisfy ATM features such as ATM cell ordering and no ATM cell duplication and minimize buffer requirement for ATM cell buffering. In this paper we suggest a multicast-based handoff method to supp$\alpha$t lossless connection as well as to minimize buffer overhead. It establishes a dynamic multicast connection between source terminal and wireless member AP (access point)s. When the mobile terminal receives data packet correctly, it notifies the positive acknowledgement of the packet to all member APs. And member APs then release the MT related temporary buffer space for MT's future movement. Therefore member APs can eliminate unnecessary buffer usage and manage the buffer space efficiently. Analysis result shows that our handoff method has better performance in buffer requirement for lossless and seamless connection services over VCT (virtual connection tree) method and other dynamic multicast-based handoff methods.

• Journal of Navigation and Port Research
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• v.39 no.3
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• pp.141-147
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• 2015

On July 1 2012, the carriage requirement for ECDIS became mandatory in a phased-in manner. The system has since been widely used as a core bridge navigation system and as a replacement for paper charts with a back up arrangement. However operational anomalies have been found in the system internationally. IMO and IHO have recognised these anomalies and seek for solution. This study has been conducted on a survey of seafarers on the use of ECDIS with regard to anomalies identification, level of the seafarer satisfaction and requirements for further functional improvement. From the results, the ECDIS user focused requirements suggested on strengthening the level of navigational safety and efficiency. The efficiency of using main functions of ECDIS was positively evaluated. However, there were concerns regarding its operational safety.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.599-606
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• 2009

For many mission-critical related wireless sensor network applications such as military and homeland security, user's access restriction is necessary to be enforced by access control mechanisms for different access rights. Public key-based access control schemes are more attractive than symmetric-key based approaches due to high scalability, low memory requirement, easy key-addition/revocation for a new node, and no key predistribution requirement. Although Wang et al. recently introduced a promising access control scheme based on elliptic curve cryptography (ECC), it is still burdensome for sensors and has several security limitations (it does not provide mutual authentication and is strictly vulnerable to denial-of-service (DoS) attacks). This paper presents an energy-efficient access control scheme based on ECC to overcome these problems and more importantly to provide dominant energy-efficiency. Through analysis and simulation based evaluations, we show that the proposed scheme overcomes the security problems and has far better energy-efficiency compared to current scheme proposed byWang et al.

• Journal of Digital Contents Society
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• v.13 no.2
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• pp.247-254
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• 2012

The management of user requirements for information system development is a key element. The traceability has been studied in a specific method as using a traceability table or SOA related to the requirement management. But there are few case about proposing a objective and quantified evaluation method and judgement criterion for none-technical business managers. This researcher has proposed, easy to access by unprofessional and objective and qualifiable, evaluation methods and criteria of Judging for adequacy of requirements reflection in the development process of information system for the government office through a previous case study. In this study, I will give consideration to study the limitations of previous studies and improve the evaluation formula for measuring the reflection of the requirements and derive, reviewed to provide a variety of criteria for each business, through business case analysis.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.112-121
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• 2020

Recently, as the internet usage is increasing, accordingly generated text data is also increasing. Because this text data on the internet includes users' comments, the text data on the Internet can help you get users' opinion more efficiently and effectively. The topic of text mining has been actively studied recently, but it primarily focuses on either the content analysis or various improving techniques mostly for the performance of target mining algorithms. The objective of this study is to propose a novel method of analyzing the user's requirements by utilizing the text-mining technique. To complement the existing survey techniques, this study seeks to present priorities together with efficient extraction of customer requirements from the text data. This study seeks to identify users' requirements, derive the priorities of requirements, and identify the detailed causes of high-priority requirements. The implications of this study are as follows. First, this study tried to overcome the limitations of traditional investigations such as surveys and VOCs through text mining of online text data. Second, decision makers can derive users' requirements and prioritize without having to analyze numerous text data manually. Third, user priorities can be derived on a quantitative basis.