• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제14권5호
• /
• pp.2043-2060
• /
• 2020

Developed from Digital Multimedia Broadcasting (DMB), DMB+ changes the application focus fundamentally. The plus symbol "+" indicates that DMB+ is no longer for digital radio/videos, instead it works as a general data transmission technique. The merits of wireless transmission, broad coverage, high quality, information security and low building/maintenance cost make DMB+ suitable for a wide range of applications with numerous terminals and users, such as public information release, alarm and administration etc. The concept of DMB+ base station enables DMB+ to be used in building independent networks and for remote control and management, as well as for Industry 4.0. DMB+ will access into a new field that till now has been dominated by communication techniques, will open a huge commercial opportunity.

• Nuclear Engineering and Technology
• /
• 제48권3호
• /
• pp.795-798
• /
• 2016

Transmission X-ray tubes based on carbon nanotube have attracted significant attention recently. In most of these tubes, tungsten is used as the target material. In this article, the well-known simulator Geant4 was used to obtain some of the tungsten target parameters. The optimal thickness for maximum production of usable X-rays when the target is exposed to electron beams of different energies was obtained. The linear variation of optimal thickness of the target for different electron energies was also obtained. The data obtained in this study can be used to design X-ray tubes. A beryllium window was considered for the X-ray tube. The X-ray energy spectra at the moment of production and after passing through the target and window for different electron energies in the 30-110 keV range were also obtained. The results obtained show that with a specific thickness, the target material itself can act as filter, which enables generation of X-rays with a limited energy.

• 비파괴검사학회지
• /
• 제25권3호
• /
• pp.215-221
• /
• 2005

It is required to evaluate nondestructively depth of surface-breaking cracks in structures. In this paper, the self-compensated technique by laser-based ultrasound is used to measure the depth of surface-breaking defect. Optical generation of ultrasound produces a well defined pulse with reliable frequency content. It is broad banded and suitable for measurement of attenuation and scattering over a wide frequency range. The self-calibrated signal transmission data of surface wave shows good sensitivity as a practical tool far assessment of surface-breaking defect depth. It is suggested that the relationship between the signal transmission and crack depth can be used to predict the surface-breaking crack depths in structures.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1040-1047
• /
• 2008

Hypoid gears are widely used in rear drive and 4WD vehicle axles. Investigation of their sensitivity to deflections is one of the most important aspects of their design and optimization procedures. The deflection test is performed in the actual gear mounting using completely processed gear. This test should cover the full operating range of gear loads from no load to peak load. Under peak load the contact pattern should extend to the tooth boundaries without showing a concentration of the contact pattern at any point on the tooth surface. Transmission error is tested on an axle assembly triaxial real car load condition.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.687-689
• /
• 2014

This paper deals with the optimal muffler model by using acoustic analysis and CFD(computational fluid dynamics) analysis. The complicated muffler model could be better noise reduction performance. However, it could be worse affected to back-pressure performance by pressure drop in working fluid. High back-pressure is caused to low system efficiency. Therefore, it is important for the muffler design to consider the pressure drop. The muffler models are changed their partition plate position. Acoustic power transmission loss(TL) and pressure drop of working fluid are calculated by using computational analysis and used to build database for finding their trends. The optimal muffler model in user-interested frequency range could be selected by analyzing this database.

• 한국통신학회논문지
• /
• 제21권3호
• /
• pp.763-770
• /
• 1996

In this paper, the Single-stage Transmission type Injectiong-Locked Oscillator(STILO) was designed and fabicated for the Active Integrated Phased Array Antenna(AIPAA) system. The STILO, which was designed and fabricated by injection-locked technique and hair-pin resonator, has the same 210MHz frequency tuning range of the Voltage Controlled Oscillator(VCO) used by varactor. The locking bandwidth of STILO with 11.5MHz bandwidth, is much better than that of the Injection-Locked Dielectric Resonator Oscillator(ILDRO), And the STILO has the improved noise characteristics in AM, FM, and PM. This STILO is useful for the AIPAA, the coupled VCO array, an the MMIC structure.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
• /
• pp.967-975
• /
• 2009

In order to control differential settlement and to secure the safety of super structure on a high rock embankment the designed static compaction is changed with dynamic compaction and piled raft method. The parameters for dynamic compaction design are obtained from a pilot test. In addition, numerical analyses are also carried out to figure out the length and quantity of piled raft that can restraint the differential settlement within allowance range.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 A
• /
• pp.305-307
• /
• 2003

This paper presents an apparent impedance calculation procedure for distance relaying of transmission line involving FACTS (Flexible AC Transmission System) devices, particularly the UPFC (Unified Power Flow Controller), between Kangjin and Jangheung in Korea. With the changes of UPFC's parameters, the measurement and protective range (trip boundaries) of the adaptive distance relay can also be changed. So, it is the most important part in the field of system protection to analyze the operating characteristic of relaying system. The presence of UPFC significantly affects the trip boundaries which are also adversely affected by fault resistance combined with remote end infeed. This paper presents the apparent impedance calculations and the distance relay setting characteristics for faults involving the UPFC in the KEPCO system.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2002년도 동계연구발표회 논문개요집
• /
• pp.200-201
• /
• 2002

Recently, a countermeasure for the electromagnetic noise emission on RF integrated transmission line using the loss generation of ferromagnetic thin films is briefly suggested$\^$1,2/. Without the magnetic film, the noise harmonics of the signal pass through the transmission line with only a little attenuation. The ideal role of magnetic film is not to raise insertion losses in the pass-band and to give as large attenuation as possible to eliminate the noise harmonics at the stop-band, the frequency range higher than the meaningful signal as shown in Fig. 1. and Fig. 2. (omitted)

• Journal of Biosystems Engineering
• /
• 제27권1호
• /
• pp.19-24
• /
• 2002

According to the field test, the transient power transmission efficiency of a tractor driveline fluctuated in a range of 56 to 86% and the mean value was about 72.5%. Therefore, the constant efficiency model commonly used for a simulation of power performance was not proper far predicting such a variable of efficiency. In order to predict power efficiency more accurately, new concepts of the maximum efficiency and drag torque were introduced and a new model based on the these concepts was proposed. The difference between measured and model-predicted efficiencies was about 1.5% in average with a standard deviation of 1.1%. The new power efficiency model was expected to enhance the accuracy of predicting power transmission efficiencies of tractor drivelines.