• Journal of the Korean BIBLIA Society for library and Information Science
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• v.30 no.3
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• pp.5-30
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• 2019

The purpose of this study is to suggest an improvement of digitization criteria for records that can faithfully reproduce the contents and properties of original records by complementing the problems and deficiencies of "NAK 26:2018(v2.0) Digitization Criteria for records". Thus, this study proposes a technical standard improvement that should be applied to the digitization process for records not produced in the form of digital files by comparing and analyzing the criteria for digitization of records in Korea with overseas digitization criteria, guidelines, recommendations, and so on. In addition, verifying the validity on this study by interviewing experts from the record-related institutions. As a result, suggested a final improvement of criteria for digitization of records such as applying non compression-Lossless codecs, proposing appropriate resolution values for each type of records, audio channels, frame rates, scan methods, and criteria for microform types.

• Journal of the Korea Institute of Building Construction
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• v.19 no.5
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• pp.391-399
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• 2019

This study reviewed the possibility of recycling into exhausted aggregate resources in Korea as a means of utilizing coal gasification slag(CGS) from integrated gasification combined cycle(IGCC) while being commissioned in order to introduce the new system to Korea. In other words, in order to solve the problem of insufficient aggregate resources, CGS generated by IGCC as a residual aggregate for concrete secondary products, which is an empty mortar, was considered to replace CGS in the range of 0 to 100 % for mixed residual aggregate mixed with crushed sand A(CSa) of good quality and sea sand(SS) of deep particles, which are the most commonly used in the domestic construction industry. According to the study, replacing CGS with CSa or crushed sand B(CSb)+SS by 25 % to 50 % resulted in good results in the aspect of the granularity of the aggregate and the workability and compressive strength of cement mortar, which were found to be usable.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.3
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• pp.183-188
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• 2011

According to increased multimedia data(i.e., MPEG video stream) in mobile application, protecting data becomes an important problem in the multimedia data delivery. SECMPEG is a selective encryption approach for protecting multimedia data. However, the computational overhead of SECMPEG's security level 3 is quite large because it encrypts the whole I-frames whose size is relatively larger than P/B-frames. Therefore, we need to analyze the characteristics of MPEG2 standard and derive an effective encryption of the I-frames. In this paper, we propose a slice-level, selective encryption approach by using the error-propagation characteristics of I-frames by a receiver. Our experimental results show that the proposed approach can reduce the execution time of SECMPEG's security level 3 by a factor of 30 without degradation of the security.

• Journal of the Korea Institute of Building Construction
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• v.23 no.3
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• pp.285-293
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• 2023

In this research, we embarked on a meticulous analysis of the challenges inherent in real-world scenarios relating to the durability design standards of engineered concrete structures and the assessment of carbonation durability in concrete guidelines. Our investigation brought to light substantial issues concerning constructability and quality assurance. The genesis of these problems is the exclusive application of prescribed strength to exterior walls, neglecting other elements to facilitate smoother licensing procedures. While this methodology aims to mitigate financial constraints in alignment with enhanced standards, it invariably invites complications. Furthermore, it is imperative to resolve the uncertainty surrounding durability evaluations by establishing a clear and definitive objective. Alongside this, actionable steps must be formulated to forestall the emergence of fissures between the floors of residential buildings, particularly apartment complexes. It is equally essential to tackle issues connected to application by devising a comprehensive management strategy for potential cracking during the phase of maintenance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1D
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• pp.71-77
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• 2010

This study presented the operation method through of productivity on eight analysis work items (TBM boring, cutter check and exchange, TBM maintenance, succeeding facilities, reinforcement in tunnel, operation alternation, a tram car) which have developed equipment at WRITH with TBM a waterway tunnel works. It was inquired lose time with analyzed result by work items and removed lose time. It was analyzed TBM boring length, TBM boring length percentage and TBM boring length time. This study analyzed TBM operation utility factor of a foreign work with TBM operation boring length percentage, a monthly average boring length, pure boring length percentage etc. and assumed a monthly average boring length and a monthly average boring length of rise forecast. Based on analyzed Data, TBM boring has been forecasted propriety pure boring length at compressive strength $675{\sim}1662kgf/cm^2$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.4 s.56
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• pp.126-136
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• 2009

The sprayed FRP strengthening technique is combining the Glass fiber and Polyester resin in open air and spraying randomly at concrete's surface with high-speed compressed air. Then it strengthens the structures with a new technique evaluated the structural performance. We applied it to concrete beam and tested for flexural strength, depended on Korea Standard(KS F 2408). Then based on the result of flexural strength, the properties were proposed that applying to structures. Based on the experiment, we have evaluated structural performance by the experiment. 1/5 scale prestressed concrete I-beam were made by Korean Highway's typical drawing in 1993. With these test results, 49.8% increased in flexural strength, improvement of the behavior of serviceability state, and strengthening was surely effective for controlling deflection and crack of structure. Consequently, it can be summarized that Sprayed FRP technique has prospect to improve the performance of structure.

• Korean Journal of Agricultural Science
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• v.13 no.1
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• pp.90-102
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• 1986

This study was performed to obtain the basic data which can be applied to the use of concretes. The data was based on the properties of concrectes depending upon water-cement ratios and addings to compare those of plain concrete. The results obtained were summarized as follows; 1. In case the proper quantity of water reducing agent was added, unit weight of water is decreased to 12.9% with WR-LG of water reducing set standarding agent and to 8.6% with HF-SP of high fluid agent and to 17.2% with AH-WR of water reducing set accelerating agent, respectively, as compared with plain concrete. With the increase of water reducing agent content unit weight of water was greatly decreased. 2. The adding rate of water reducing agent which produce maximum strength was 0.2% with WR-LG and 0.4% with HF-SP and AH-WR, respectively. The increasing rates of strengths were showed that WR-LG is 24.1% and that HF-SP is 41.8% and that AH-WR is 43.3%, respectively, as compared with plain concrete. 3. The correlations between compressive and tensile strength were highly significant as a straight line. the multiple regression equations of compressive and tensile strength were computed with the variables of curing age and addition of water reducing agent. They were highly significant. 4. In case the proper quantity of water reducing agent was added, the correlations between water-cement ratio and compressive strength were highly significant as a straight line. The increasing rates of strength were showed higher than the decreasing rates of water cement-ratio.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.574-584
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• 2006

Recently, ISO/IEC 23000 (also known as 'MPEG-A') has proposed a new file format called 'MAF(Multimedia Application File Format)[1]' which provides a capability of integrating/storing the widely-used compression standards for audio and video and the metadata in MPEG-7 form into a single file format. However, it is still very hard to verify the usefulness of MPEG-A in the real applications because there is still no real system that fully implements this standard. In this thesis, a design and implementation of a multimedia retrieval system based on MPEG-A standard on PC and mobile device is presented. Furthermore, an extension of MPEG-A for describing the metadata for video is also proposed. It is selected and defined as a subset of MPEG-7 MDS[4] and TV-anytime[5] for video that is useful and manageable in the mobile environments. In order to design the multimedia retrieval system based on MPEG-A, we define the system requirements in terms of portability, extensibility, compatibility, adaptability, efficiency. Based on these requirements, we design the system which composed of 3 layers: Application Layer, Middleware Layer, Platform Layer. The proposed system consists of two sub-parts, client-part and server-part. The client-part consists of MAF authoring tool, MAP player tool and MAF searching tool which allow users to create, play and search the MAF files, respectively. The server-part is composed of modules to store and manage the MAF files and metadata extracted from MAF files. We show the usefulness of the proposed system by implementing the client system both on MS-Windows platform on desk-top computer and WIPI platform on mobile phone, and validate whether it to satisfy all the system requirements. The proposed system can be used to verify the specification in the MPEG-A, and to proves the usefulness of MPEG-A in the real application.

• The Korean Journal of Rheology
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• v.11 no.1
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• pp.18-27
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• 1999

Predicting the deformation behaviors of sheets in thermoforming processes has been a daunting challenge due to the strong nonlinearities arising from very large deformations, mold-polymer contact condition and hyperelasticity constitutive equations. Nonlinear numerical analysis is always required to face this challenge especially for realistic processing conditions. In this study a 3-D algorithm and the membrane approximation are developed for thermoforming processes. The constitutive equation is expressed in terms of the 2nd Piola-Kirchhoff stress tensor and the Cauchy-Green deformation tensor. The 2-term Mooney-Rivlin model is used for the material model equation. The algorithm is established by the finite element formulation employing the total Lagrangian coordinate. The deformation behavior and the stress distribution results of 3-D algorithm with various point boundary conditions are compared to those of the membrane approximation algorithm. Also, the slip boundary condition and the no-slip boundary condition are applied for the systems that have molds. Finally, the effect of sheet temperatures on the final thickness distribution is investigated for the ABS material.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.153-166
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• 1991

In an attempt to investigate the effect of intermedate principal stresses which are related to the stress-strain behavior of standard sands, a series of three-Principal stress control tests were conducted for individual stress paths. The results have shown that shear strengths of sands vary with the stress paths. The variations in internal friction angle are accorded with the Habibs stress parameter, b which represents Stress paths, showing on abropt increase at the values between 0.0 and 0.268, a moderate level between 0.268 and 0.682, and a slight decrease between 0.682 and 1.0 However, the friction angles under a triaxial extention state, were found relatively larger than under a triaxial compression state. In general, such veriations were found to have the same tendency without any relevant relation with the density of specimens and confining pressures. Therefore, it is concluded, that the shear strength of sands are positively influeced by the intermediate principal stresses present in the media. And the influnce of intermediate principal stresses on shear strengths of sands found from the present study are well compared with the previous studies by Lade-Duncan and Matsuoka-Nakai revealing a similar tendency within the failure criteria proposed by them.