• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.4
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• pp.194-202
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• 2019

Reliability analysis of the components frequently starts with the data that manufacturer provides. If enough failure data are collected from the field operations, the reliability should be recomputed and updated on the basis of the field failure data. However, when the failure time record for a component contains only a few observations, all statistical methodologies are limited. In this case, where the failure records for multiple number of identical components are available, a valid alternative is combining all the data from each component into one data set with enough sample size and utilizing the useful information in the censored data. The ROK Navy has been operating multiple Patrol Killer Guided missiles (PKGs) for several years. The Korea Multi-Function Control Console (KMFCC) is one of key components in PKG combat system. The maintenance record for the KMFCC contains less than ten failure observations and a censored datum. This paper proposes a Bayesian approach with a Dirichlet mixture model to estimate failure time density for KMFCC. Trends test for each component record indicated that null hypothesis, that failure occurrence is renewal process, is not rejected. Since the KMFCCs have been functioning under different operating environment, the failure time distribution may be a composition of a number of unknown distributions, i.e. a mixture distribution, rather than a single distribution. The Dirichlet mixture model was coded as probabilistic programming in Python using PyMC3. Then Markov Chain Monte Carlo (MCMC) sampling technique employed in PyMC3 probabilistically estimated the parameters' posterior distribution through the Dirichlet mixture model. The simulation results revealed that the mixture models provide superior fits to the combined data set over single models.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.264-272
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• 2008

In ubiquitous geographic information environment, the users are provided with geographic information anywhere and any time on their needs by any types of devices and communication media. The unique location ID, ePosition, is a new technology to support UBGI environment, using a logical location ID instead of physical location of a point of interest. Domain names of plural ePosition servers, where location information with its ePosition is stored, needs to be registered in DNS for some service through Internet. For better ePosition service of the type of public service like email service, a set of DNS resource records can be newly defined. This paper suggests a new DNS resource record EPO for implementation of the ePosition service through Internet.

• Publications of The Korean Astronomical Society
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• v.19 no.1
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• pp.83-92
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• 2004

In this paper, we introduce the development of the large storage system in order to record the observed space radio signal in the Korean VLBI Network(KVN) with high-speed. The KVN is the Very Long Baseline Interferometery(VLBI) to observe the birth of star, the structure of space by constructing radio telescope with diameter 21m at the Seoul, Ulsan, Jeju from 2001 to 2007 years. To do this, Korea Astronomy Observatory joined the international consortium for developing the high-speed large storage system(Mark 5), which is developed by MIT Haystack observatory. The Mark 5 system based on hard disk has to record up to 1 Gbps the observed space radio signal. The main features of Mark 5 system are as follows; First it is able to directly record the input data to the hard disk without PC1(Peripheral Component Interconnect) internal bus, and the second, it has two hard disk banks, which are able to hot-swap ATA/IDE type very cheap up to 1 Gbps recording and playback. The third is that it follows the international VLBI standard interface hardware(VSI-H). Therefore it can be connect directly the VSI-H type system at the input/output. Finally it also supports e- VLBI(Electronic-VLBI) through the standard Gigabits Ethernet connection.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.239-244
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• 2014

As the usefulness of mobile device is kept growing the privacy of the cloud computing is receiving more attentions. Even though many researches and solutions for privacy matters are suggested we are still worrying about the security problems. In addition most of cloud computing systems uses file-level synchronization which make it difficult to modify a part of a file. If we use data-centric app that stores data on embedded DBMS such as SQLite, a simple synchronization may incur some loss of information. In this paper we propose a solution to build a personal cloud that supports record-level synchronization. And we show a prototype system which uses RESTful web services and the same schema on mobie devices and the cloud storage. Synchronization is achieved by using a kind of optimistic concurrency control.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2481-2490
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• 2015

The issue of PHR is maintained on the server will be in the hospital. PHR information stored on the server, such as a patient's illness and treatment is very sensitive information. Therefore, patients should be guaranteed the protection of privacy. In addition, the PHR should be allowed to group access of it's approach. Therefore, in this paper the proposed group signature using hierarchical identity-based encryption schemes into can guarantee the PHR data privacy. The session key generated by group signature, it is use a tiered approach. The generated session keys safe PHR data transmission is possible. The proposed method is average 80% than the PKI encryption and ID-based encryption rather than average 50% the algorithm processing is more efficient

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.6
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• pp.916-921
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• 2018

Recently, interest in autonomous vehicle has increased, and autonomous driving capability is also increasing. Depending on the autonomous driving ability, the maximum number of steps is divided into 6 steps. The higher the step, the less the involvement of the person in the running, and the person does not need to be involved at the highest stage. Today's autonomous vehicles have been developed high level, but solutions are not clearly defined in case of an accident, so only the test run is possible. Such an accident occurring during traveling is almost inevitable, and it is judged who has made a mistake in case of an accident, which increases the punishment for the accident. Although a black box is used to clarify such a part, it is easy to delete a record, and it is difficult to solve an accident such as a hit-and-run. In this paper, i design a driving record system using black chain to solve accidents.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.4
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• pp.123-128
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• 2020

As the use of digital devices is becoming more commonplace, digital forensics techniques recover data to collect physical evidence during the investigation. Among them, the file forensics technique recovers deleted files, therefore, it can recover the database by recovering all files which compose the database itself. However, if the record is deleted from the database, the modified record contents will not be restored even if the file is recovered. For this reason, the database forensics technique is required to recover deleted records. Database forensics obtains metadata from database configuration files and recovers deleted records from data files. However, record recovery is difficult if database metadata such as block size cannot be obtained from the database. In this paper, we propose three methods for obtaining block size, which is database metadata. The first method uses the maximum size of free space in the block, and the second method uses the location where the block appears. The third method improves the second method to find the block size faster. The experimental results show that three methods can correctly find the block size of three DBMSes.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.173-180
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• 2008

Certified e-Document Authority keep it with protection legal as a system a guarantee and identifies originality of an e-Record, It presume to be authenticity e-Records and contents of an e-Record prove what was not changed. But, e-Records has high medium degree of dependence and loss danger of information has very high problems. In addition, Because correction(attachment and deletion) and a revision of information are easy, a problem for integrity and the originality of an e-Record is caused. Existing system show the following inefficient. For the originality guarantee, an existing e-Documents encryption method accomplishes a encrypted process of a whole document with a symmetric key, if the information revised midway, the whole documents content must accomplish re-scanning and re-encryption process again. To get over such inefficient, this paper maximize efficiency which occurred at the time of partial information revision request by encryption and managing using the link information based on the linkage characteristics of the each page on the registered requested e-Documents, It was able to increase security configuration by minimizing problems on an information exposure through increasing complicated of the key management.

• Convergence Security Journal
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• v.15 no.7
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• pp.75-84
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• 2015

In an "NTFS Index Record Data Hiding" method messages are hidden by using file names. Windows NTFS file naming convention has some forbidden ASCII characters for a file name. When inputting Hangul with the Roman alphabet, if the forbidden characters for the file name and binary data are used, the codes are convert to a designated unicode point to avoid a file creation error due to unsuitable characters. In this paper, the problem of a file creation error due to non-admittable characters for the file name is fixed, which is used in the index record data hiding method. Using Hangul with Roman alphabet the characters cause a file creation error are converted to an arbitrary unicode point except Hangul and Roman alphabet area. When it comes to binary data, all 256 codes are converted to designated unicode area except an extended unicode(surrogate pairs) and ASCII code area. The results of the two cases, i.e. the Hangul with Roman alphabet case and the binary case, show the applicability of the proposed method.

• The KIPS Transactions:PartD
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• v.18D no.5
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• pp.403-414
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• 2011

Recently, smart phones based on Android platform have been widely used, and lots of applications have been developed. Data generated from an application are frequently transferred to other applications. Therefore, a method that can easily transfer or share meta-data among applications is required. Generally meta-data created by android applications are java objects. The android platform uses clipboard, intent and content provider in order to transfer data among the applications. However, those ways are designed to transfer data as a record. So these methods have to marshall the object to a record and unmarshall the record to an object. In this paper, we designed and implemented the MetaService which can transfer any type of object made by applications. When the MetaService is used, we can reduce complex implementations such as clipboards and content providers and we can reduce many bugs. Therefore, we can make the applications simple and increase productivity.