• Journal of the Korean Wood Science and Technology
• /
• v.45 no.6
• /
• pp.872-882
• /
• 2017

The objective of this study was to evaluate the properties of bamboo oriented strand board (B-OSB) from andong (Gigantochloa psedoarundinacea) and betung (Dendrocalamus asper) with and without steam treatment. Strands were steam-treated at $126^{\circ}C$ for 1 h under 0.14 MPa pressure. The extractive content of bamboo strands before and after steam treatment were determined according to a standard (TAPPI T 204 om-88). Three-layer B-OSB with the core layer perpendicular to the surface and back layers were formed and binded with 8% of phenol formaldehyde (PF) resin with the addition of 1% of wax. The evaluation of physical and mechanical properties of the boards were conducted in accordance with the JIS A 5908:2003 standard. The results showed that steam treatment of bamboo strands significantly reduced the extractive content. Steam treatment tended to increase the dimensional stability and mechanical properties of B-OSB from andong and betung. The results showed that the dimensional stability and bending strength of B-OSB from betung was higher than those of andong. The internal bond strength of B-OSB from andong was higher than betung owing to a greater amount of extractives dissolved during the steam treatment.

• Journal of Industrial Convergence
• /
• v.17 no.3
• /
• pp.39-49
• /
• 2019

This study, as a study on building platforms for smart campus ecosystem, took an approach that reflected the needs of various stakeholders of smart campus, and focused on functions to help them strengthen their competitiveness and advance into society by focusing on the learning of the most important university student users, college life, and social connection. First, we looked at the theories related to smart campus construction through prior research, and next, through domestic and international environmental analysis and trend analysis, we designed and presented a target model for e-portfolio focusing on core competency development and support system for Industry-Academic Cooperation, and proposed the main point for continuous smart campus development model.

• Design & Manufacturing
• /
• v.13 no.2
• /
• pp.44-48
• /
• 2019

Motor core products are used as materials for electrical steel sheets and cold-rolled steel sheets according to the performance of motors. The cemented carbide material of the mold punch applied to the motor core material causes many troubles due to abrasion and burr problem. The selection of these materials has a great effect on the production life, mass production, product quality as well as mold life. The cemented carbide applied to the products of the motor core is recognized as a very important part. In this study, cold rolled steel sheet was applied to motor core SCP-1 steel 1.0mm, and The effects of abrasion and punching oil on the shear process were investigated for the selection of cemented carbide. Experiments were conducted to select and apply cemented carbide only for the motor core punch optimized for cold rolled steel. The results showed that the cemented carbide material of $CDK3^{***}$ produced the least wear and burrs.

• The Journal of the Korea Contents Association
• /
• v.13 no.11
• /
• pp.510-521
• /
• 2013

The awareness of education service is undergoing a transition from demand side to supply side. This study 1) develops an evaluation model of education service composed of three core factors(curriculum content, professor activities, job search activity) and additional factors(public welfare, education environment, campus life), 2) verifies a model using the structural equation model, 3) calculates the satisfaction measurement index of education service, and 4) proposes the results of IPA for evaluating the satisfaction measurement of education service. The results show significant notions that core factors(curriculum content, professor activities, job search activities) and additional factors(public welfare, education environment, campus life) determine students satisfaction, and that student satisfaction effects the recommend purpose significantly. Especially, student satisfaction influenced curriculum content, job search activity, campus life, public welfare, professor activities, education environment in order. This study provides improved strategic implications based on the calculated results of component satisfaction measurement index, and the results of IPA.

• Journal of the Korean Wood Science and Technology
• /
• v.47 no.4
• /
• pp.519-532
• /
• 2019

The objectives of this study were to evaluate the effects of shelling ratio and resin content on the properties of bamboo oriented strand board (BOSB) from betung (Dendrocalamus asper) and to determine the correlation between the results of dynamic and static bending tests. Strands were steam-treated at $126^{\circ}C$ for 1 h under 0.14 MPa pressure and followed by washing with 1% NaOH solution. Three-layer BOSB with the core layer perpendicular to the surface was formed with shelling ratios (face:core ratio) of 30:70; 40:60; 50:50; 60:40 and binded with 7% and 8% of phenol formaldehyde (PF) resin with the addition of 1% of wax. The evaluation of physical and mechanical properties of BOSB was conducted in accordance with the JIS A 5908:2003 standard and the results were compared with CSA 0437.0 standard for commercial OSB (Grade O-1). Non-destructive testing was conducted using Metriguard Model 239A Stress Wave Timer which has a wave propagation time from 1 to $9,999{\mu}s$ and a resolution of $1{\mu}s$. BOSB with 8% resin content showed better physical and mechanical properties than those with 7% resin content. The increase of the face layer ratio improved the strength of BOSB in parallel direction to the grain. The results suggested that shelling ratio of 50:50 could be used as a simple way to reduce PF resin requirements from 8% to 7% and to meet the requirements of CSA 0437.0 standard. The results of non-destructive and destructive tests showed a strong correlation, suggesting that non-destructive test can be used to estimate the bending properties of BOSB.

• Structural Engineering and Mechanics
• /
• v.67 no.1
• /
• pp.69-78
• /
• 2018

The study presented herein focused on the change in hysteretic force-deformation behavior of lead rubber bearings (LRBs). The material model used to idealize response of LRBs under cyclic motion is capable of representing the gradual attrition in strength of isolator unit on account of lead core heating. To identify the effect of loading history on the hysteretic response of LRBs, a typical isolator unit is subjected to cyclic motions with different velocity, amplitude and number of cycles. Furthermore, performance of an LRB isolated single degree of freedom system is studied under different seismic input levels. Finally, the significance of lead core heating effect on LRBs is discussed by considering the current design approach for base isolated structures. Results of this study show that the response of an LRB is governed strongly by the amplitude and number of cycles of the motion and the considered seismicity level.

• Journal of the Korean Institute of Educational Facilities
• /
• v.19 no.5
• /
• pp.11-20
• /
• 2012

The student hall and its convenient facilities are hot-core space for various student activities in university campus. It has been for most of the student a place of sweet memories and romance imprinted by a positive image of a cozy atmosphere of unique eating establishments or student hectic activities that used to take place. However, it is questionable whether that facilities are open for all of the students and other users including the handicapped. Therefore, the purpose of this study is to evaluate student convenient facilities and to provide an improvement guideline for the wellbeing of students and other users, based on universal design concept. For that purpose, eight universities were selected for an investigation and 81 survey items were developed based on universal design concept; supportive, adaptable, accessible, and safety-oriented design. The analysis found that accessibility to main entry areas, main entry doors, stairs, and handicapped parking were positively evaluated, while information system for handicapped, handicapped public bath, and corridors lacked some notion of supportive and accessible design. Finally the study suggested some useful planning and design guidelines for an extensive and precise application of universal design concept.

• International Journal of Computer Science & Network Security
• /
• v.24 no.6
• /
• pp.23-32
• /
• 2024

Mobile Ad hoc Network is a network of multiple wireless nodes which communicate and exchange information together without any fixed and centralized infrastructure. The core objective for the development of MANET is to provide movability, portability and extensibility. Due to infrastructure less network topology of the network changes frequently this causes many challenges for designing routing algorithms. Many routing protocols for MANET have been suggested for last few years and research is still going on. In this paper we review three main routing protocols namely Proactive, Reactive and Hybrid, performance comparison of Proactive such as DSDV, Reactive as AODV, DSR, TORA and Hybrid as ZRP in different network scenarios including dynamic network size, changing number of nodes, changing movability of nodes, in high movability and denser network and low movability and low traffic. This paper analyzes these scenarios on the performance evaluation metrics e.g. Throughput, Packet Delivery Ratio (PDR), Normalized Routing Load(NRL) and End To-End delay(ETE).This paper also reviews various network layer security attacks challenge by routing protocols, detection mechanism proposes to detect these attacks and compare performance of these attacks on evaluation metrics such as Routing Overhead, Transmission Delay and packet drop rates.

• Journal of the Korean Mathematical Society
• /
• v.60 no.5
• /
• pp.1073-1085
• /
• 2023

A partition of n is called a t-core partition if none of its hook number is divisible by t. In 2019, Hirschhorn and Sellers [5] obtained a parity result for 3-core partition function a3(n). Motivated by this result, both the authors [8] recently proved that for a non-negative integer α, a3αm(n) is almost always divisible by an arbitrary power of 2 and 3 and at(n) is almost always divisible by an arbitrary power of pji, where j is a fixed positive integer and t = pa11pa22···pamm with primes pi ≥ 5. In this article, by using Hecke eigenform theory, we obtain infinite families of congruences and multiplicative identities for a2(n) and a13(n) modulo 2 which generalizes some results of Das [2].

• Proceedings of the KIPE Conference
• /
• 2019.11a
• /
• pp.31-33
• /
• 2019

본 논문에서는 고주파 변압기 대신 무선 전력 전송 시스템을 적용해 양방향 전력 전송을 가능케 해주는 loosely coupled dual-active-bridge 컨버터에서, 코일 간 전송 효율을 높이기 위한 코일 형상 설계에 관한 연구를 진행하였다. 유한 요소법을 통해 여러 형태의 페라이트 코어에 대해 해석했다. 페라이트 코어 형태가 I-자 일 때 가장 높은 quality factor의 코일을 얻을 수 있었다. 또한, I-core의 ferrite plate의 크기에 따라 무선 전력 전송의 효율을 결정하는 코일의 coupling coefficient와 코일의 quality factor가 변하고 trade-off 관계가 있음을 확인하였다. 3cm의 air-gap에 대해 최대 효율을 가지는 코일 형상을 설계하여 시뮬레이션을 통해 97.8%의 코일간 전송효율을 얻었다.