• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.7
• /
• pp.774-781
• /
• 2014

This paper presents a fingerprint database construction method for WLAN RSSI (Received Signal Strength Indicator)-based indoor positioning. When RSSI is used for indoor positioning, the fingerprint method can achieve more accurate positioning than trilateration and centroid methods. However, a FD (Fingerprint Database) must be constructed before positioning. This step is a very laborious process. To reduce the drawbacks of the fingerprint method, a radio propagation model-based FD construction method is presented. In this method, an FD can be constructed by a simulator. Experimental results show that the constructed FD-based positioning has a 3.17m (CEP) error. In this paper, a spatial correlation method is presented to estimate the NLOS(Non-Line of Sight) error included in the FD constructed by a simulator. As a result, the NLOS error of the FD is reduced and the performance of the error compensated FD-based positioning is improved. The experimental results show that the enhanced FD-based positioning has a 2.58m (CEP) error that is a reasonable performance for indoor LBS (Location Based Service).

• Structural Engineering and Mechanics
• /
• v.69 no.5
• /
• pp.579-589
• /
• 2019

Numerous experimental studies have been conducted on reinforced concrete (RC) beams strengthened in shear with externally bonded fiber reinforced polymer (EBFRP). The objectives of this work are to study the behavioral trends of shear strengthened EBFRP RC beams after updating the existing database. The previously published databases have been updated, enriched and cross checked for completeness, redundancy and consistency. The updated database now contains data on 698 EBFRP beams and covers the time span from 1992 to 2018. The collected database then refined applying certain filters and used to investigate and capture better interactions among various influencing parameters affecting the shear strength of EBFRP beams. These parameters include the type and properties of FRP, fiber orientation as well as the strengthening scheme, the shear and the longitudinal steel reinforcement ratios, the shear span ratio, and the geometry of the member. The refined database is used to test the prediction accuracy of the existing design models. Considerable scatters are found in the results of all tested prediction models and in many occasions the predictions are unsafe. To better understand the shear behavior of the EBFRP RC beams and then enhance the prediction models, it was concluded that focused experimental programs should be carried out.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.25 no.5
• /
• pp.1143-1151
• /
• 2015

Extensible Storage Engine (ESE) database is a database developed by Microsoft. This database is used in web browser like Internet Explorer, Spartan and in Windows system with Windows Search, System Resource Usage Monitor. Previous ESE database viewer can display an incorrect result and can't read the file depending on collected environment and status of files. And the deleted record recovery tool is limited to some program and cannot recover all tables. This paper suggests the universal recovery method for deleted records and presents the experimental results through development of tool.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.5
• /
• pp.473-482
• /
• 2008

In this paper we propose an expert system for content-based image retrieval with object database. The proposed system finds keyword by using knowledge-base and feature of extracted object, and retrieves image by using keyword based image retrieval method. The system can decrease error of image retrieval and save running time. The system also checks whether similar objects exist or not. If not, user can store information of object in object database. Proposed system is flexible and extensible, enabling experts to incrementally add more knowledge and information. Experimental results show that the proposed system is more effective than existing content-based image retrieval method in running time and precision.

• Journal of Information Processing Systems
• /
• v.8 no.1
• /
• pp.85-100
• /
• 2012

The Hartley transform based feature extraction method is proposed for fingerprint matching. Hartley transform is applied on a smaller region that has been cropped around the core point. The performance of this proposed method is evaluated based on the standard database of Bologna University and the database of the FVC2002. We used the city block distance to compute the similarity between the test fingerprint and database fingerprint image. The results obtained are compared with the discrete wavelet transform (DWT) based method. The experimental results show that, the proposed method reduces the false acceptance rate (FAR) from 21.48% to 16.74 % based on the database of Bologna University and from 31.29% to 28.69% based on the FVC2002 database.

• Journal of the Society of Naval Architects of Korea
• /
• v.59 no.4
• /
• pp.200-206
• /
• 2022

This study is to develop database by an experimental method for the development of condition based maintenance for auxiliary equipment in marine engine systems. Existing ships have been performing regular maintenance, so the actual measurement data development is very incomplete. Therefore, it is best to develop a database on land tests. In this paper, a database developed by an experimental method is presented. First, failure case analysis and reliability analysis were performed to select a failure mode. For the failure simulation test, a test bed for land testing was developed. The failure simulation test was performed based on the failure simulation scenario in which the failure simulation test plan was defined. A 1.5TB failure simulation database has been developed, and it is expected to serve as a basis for ship failure diagnosis and prediction algorithm model development.

• Journal of Information Processing Systems
• /
• v.18 no.3
• /
• pp.374-388
• /
• 2022

Database systems usually have many parameters that must be configured by database administrators and users. RocksDB achieves fast data writing performance using a log-structured merged tree. This database has many parameters associated with write and space amplifications. Write amplification degrades the database performance, and space amplification leads to an increased storage space owing to the storage of unwanted data. Previously, it was proven that significant performance improvements can be achieved by tuning the database parameters. However, tuning the multiple parameters of a database is a laborious task owing to the large number of potential configuration combinations. To address this problem, we selected the important parameters that affect the performance of RocksDB using random forest. We then analyzed the effects of the selected parameters on write and space amplifications using analysis of variance. We used a genetic algorithm to obtain optimized values of the major parameters. The experimental results indicate an insignificant reduction (-5.64%) in the execution time when using these optimized values; however, write amplification, space amplification, and data processing rates improved considerably by 20.65%, 54.50%, and 89.68%, respectively, as compared to the performance when using the default settings.

• KIPS Transactions on Software and Data Engineering
• /
• v.9 no.4
• /
• pp.123-128
• /
• 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 Korea Society of Industrial Information Systems
• /
• v.9 no.3
• /
• pp.19-31
• /
• 2004

The purpose of this study is to show a case integration of web programming with database using Visual InterDev as a conceptual client and Web Server as server, Through this case study, we can see how easily dynamic web database programming used in Internet and Interanet can be developed in one integrated design environment such as Visual InterDev eliminating the inconvenience of developing database file and web page separately. Some literature survey and experimental practices were done to provide future developers with the principles and methodologies of developing web database programing using Visual InterDev with much less coding efforts and more convenient and easy way compared to other web developing tools.

• The Journal of Information Technology and Database
• /
• v.6 no.2
• /
• pp.45-57
• /
• 1999

This paper makes an attempt to find a systematic portion of the database design process, especially using the Entity-Relationship(E-R) model. Basically, we consider three aspects as a systematic portion of the database design process. They are, the strategy that a designer selects to design an E-R diagram, designer's cognitive style, and the knowledge and preference of the database designer. An experiment has been carried out in order to verify the systematic relationship between above-mentioned three aspects and the E-R modeling performance. The target system is a professional baseball system. A normative E-R diagram was constructed based upon 48 E-R diagrams produced during the experiment. The ANOVA process has been used to analyze the results. It has been found that there exist significant differences in query-answering capacity and the completeness of the E-R model among design methods. Individual differences in cognitive styles has not been found to be significantly related to the modeling performance.