• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.27 no.1
• /
• pp.5-13
• /
• 2017

Noise complaints among neighbors in apartment building are mainly caused by floor impact noise that is structure born noise due to occupant induced floor vibration. To control this noise problems many researchers have investigated floor systems and finishing materials. Light-weight impact noise affects by finishing materials, but heavy-weight impact noise induced by heel impacts during normal walking or jumping of children is concerned with structural system and floor vibration. To figure out the characteristics of floor impact noise and transmission of floor vibration due to human activities, vibration tests were conducted in apartment buildings. Impact hammer, heel drop and walking activities were loaded at center of upstairs living room, and accelerations of slabs for both upstairs and downstairs and sound pressure levels for downstairs were measured. The acceleration ratio of transmitted floor vibration to downstairs and human induced vibration in upstairs was between 0.5 and 1.0 according to slab size, wall, and load type. And floor impact noise occurred in the range of natural frequency of slab.

• The Journal of the Korea Contents Association
• /
• v.10 no.8
• /
• pp.84-94
• /
• 2010

ESM can do and wishes to investigate ESM software field base technology and investigate ESM software technology, market, standard and evaluation certification trend and develop evaluation model of ESM software that it becomes foundation to protect ESM software effectively that develop quality evaluation model of ESM software in this research by integration security administration system that gather fire wall, IDS, VPN etc. various kind of security solution by one. That is, because reflecting requirement of ESM software, develop evaluation module and proposed evaluation example along with method of exam.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.7
• /
• pp.1361-1373
• /
• 2001

In the firewall systems of 3-tier client/server systems, in general, data transmission speed is declined rapidly according to the duplicated proxy services in application server and fire wall server. In this paper, an application server configuration containing the proxy functions of firewall system is proposed so that the high speed data transmission can be achieved. The proposed application server can form the dual-homed gateway by means of the additional network interface card. The screened router of application server forms the screened subnet gateway that can separate the internal network. The proposed server configuration is more effective in traffic control than the traditional firewall systems and provides high speed data transmission with the functions of firewall. It can be also cost-effective alternative to the firewall system.

• Journal of Advanced Marine Engineering and Technology
• /
• v.28 no.7
• /
• pp.1123-1130
• /
• 2004

Numerical simulations have been carried out to investigate the effect of nozzle hole geometry on the combustion characteristics of the large diesel engine. 6S90MC-C. Spray and combustion phenomena were examined numerically using FIRE code. Wane breakup and Zeldovich models were adopted to describe the atomization characteristics and NOx formation processes. Predictions on the cylinder peak pressure and NOx emission were first verified with the experimental data to confirm the reliability of numerical calculations. The comparison results showed good agreements within the range of 0.64% and 4.6% respectively. Finally, the effects of fuel spray angle and diameter on the engine performance were investigated numerically to find the optimum nozzle hole geometry considering fuel consumption, NOx emission and heat flux of the combustion chamber wall. It was concluded that the combustion gas recirculation in cylinder by changing fuel injection direction is an effective method to reduce NOx emission by about 10% with increasing fuel oil consumption, 1.4% in a large diesel engine.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2005.11a
• /
• pp.13-14
• /
• 2005

Multi-dimensional combustion analysis and experiment has been carried out to investigate the effects of the injector nozzle hole diameter and number on the NOx formation and fuel consumption in HYUNDAI HiMSEN engine. The behavior of spray and combustion phenomena in diesel engine was examined by FIRE code. Wave breakup and Zeldovich models were adopted to describe the atomization characteristics and NOx formation. Wallfilm model suggested by Mundo, et al. and auto-ignition model suggested by Theobald and Cheng were adopted to investigate the spray-wall interaction characteristics and ignition delay. The information of spray angle and spray tip penetration length was extracted from fuel spray visualization experiment and the fuel injection rate profile was extracted from fuel injection system experiment as an input and verification data for the combustion analysis. Next, the nine different nozzle configurations were simulated to evaluate the effect of injector hole diameter and number on the NOx formation and fuel consumption.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.37 no.5
• /
• pp.125-131
• /
• 2000

In this paper, we proposed conditional access algorithm for data confidential using smart card. This algorithm is constructed smart card and E-mail gateway for restricting of user's illegal confidential data transmission. After processing of certification procedure in smart card, each E-mail forwarded to E-mail gateway(EG). The EG selects outgoing E-mail and it is sent to fire-wall E-mail processing program, it is checked attached file in transmission mail and if it is attached file, it writes to database. This time, it can be used evidence data about user's illegal confidential data transmission, because of using registered content and smart card certification data in database. in addition to, we can get psychologically effect of prevention to send illegally, and this system can prevent spam mail in EG, also.

• Journal of architectural history
• /
• v.21 no.1
• /
• pp.155-170
• /
• 2012

The purpose of this study is to understand the architectural space of Donggung(東宮), the Prince's Palace, and Dongjo(東朝), the King's Mother and Queen's living space, in the early Joseon Dynasty. The Royal palace can be divided into three parts, political space for king, living space for king and his family and government office. So first, we should to understand the characteristics of each space in the Royal Palace. Up to now we have looked at the architectural space of Donggung(東宮) and Dongjo(東朝) in Gyeongbokgung(景福宮), one of the Royal Palace, the result of this study is as followings. Donggung which was living space for Prince consisted of Jaseondang(資善堂), Seunwhadang(承華堂) and Kyejodang(繼照堂) in the era of King Sejong Kyejodang was demolished and Seunwhadang was destroyed by fire in King Jungjong era and was not rebuilded. This buildings The buildings consisted of Jeondang, Whudang, main gate, hapmun(閤門) and corridor or fence Donggung and Dongjo was separated wall Dong consisted of many buildings for Queen dowager, Queen and many royal concubines The arrangement of Donggung and Dongjo was assumed like as the Fig2.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.16 no.2
• /
• pp.3395-3409
• /
• 1974

The purpose of this study is to test and compare the efficiency of heating-system for materials and construction of the wall, ceiling and window in soil brick house, cement house and boulder house respectively, in order to construct ideal farm houses in rural area. The results obtained were as follows: 1. In heat conservation due to construction of walls the thermal efficiency of cement brick house was equivalent to 66.3% of that of soil brick house, and boulder house 60.3% 2. In the case of ceiling, the thermal efficiency of paper ceiling was amounted to 84.2% of that of the composite ceiling (thickness 6mm veneer+thickness. l0m chaffs), and the common ceiling putting on soil above the ceiling, 76% of the composite while the efficiency of the ceiling putting on chaffs above them was 15.8% higher than that of the paper. 3. In the case of improving the window, the double type was 12% higher than. the efficiency of single type. 4. The warming velocity of conventional house was slower but the velocity of radiation was quicker than that of experimental one. It was thought to be due to unscietific constructions of the room bottom, fire inlet and chimney, 5. The temperature gradient line was not dependad upon the amount of throwing into fuel in the rural farm house. 6. It was concluded that the final thermal efficiency of the conventional farm house was 10.6% lower than that of experimental farm house.

• Convergence Security Journal
• /
• v.8 no.2
• /
• pp.71-78
• /
• 2008

This research is on the study of integrating internet and intranet that was built for their own enterprise into one network system that promises a more economic and secure use. Compared to this system, the traditional network conversion device not only has its mechanical limits, but also requires a separate network set up. This raises both interoperability and security problems and results in a higher cost. Therefore, I propose dual defence system based on the inverse multiplexing of ATM Forum and IPSec to improve network ability and deliver enhanced system reliability while reducing cost. Furthermore, I also addressed some of the weaknesses of the Scanning Attacking Method, SNMP and Spooler Port and proposed counter measures that will deal with these weakness at the dual defence system.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.4 no.3
• /
• pp.38-44
• /
• 2000

In general liquid rocket nozzles are protected from hot combustion gas by regenerative cooling techniques. But due to the complexity of the cooling system, it causes increase of system cost and frequently source of the system malfunction. Recently, instead of regenerative cooing, ablative material are used to protect combustion chamber wall and nozzle. To determine the nozzle material erosion rate and erosion shape, more than 500 hot fire test were performed by using 100 lb thrust experimental liquid rocket. Test variable were propellant feed sequence, injector, position of igniter and liquid oxygen supply temperature.