• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.11
• /
• pp.37-44
• /
• 2003

A distortion suppression technology for employing multiple inputs in 3n＋1 type current mode Max circuit is proposed using the adjustment of transconductance. If the number of input blocks of the current mode Max circuit increases, the high frequency distortion in the output signal grows. In this paper, it has been disclosed that the distortion in the multiple input Max circuit is proportional to such accumulated parasitic capacitance, to the derivative of the output signal and also to tile inverse of transconductance of the common diode-connected transistor. The proposed idea is by employing as larger transconductance of the common diode-connected transistor as possible. The effectiveness of the proposed idea has been proved through the HSPICE simulation for the current mode Max circuits with various numbers of input signals.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.9 no.4
• /
• pp.417-424
• /
• 2014

In this paper, a dual-band circular ring monopole antenna with semi-circular strip for WLAN(Wireless Local Area Networks)/WiMAX(World interoperability for Microwave Access) applications. The proposed antenna is based on a planar monopole design, and composed of half circular strip for dual-band operation which cover WLAN and WiMAX frequency bands. To obtain the optimized parameters, we used the simulator, Ansoft's High Frequency Structure Simulator(HFSS) and found the parameters that greatly effect antenna characteristics. Using the obtained parameters, the antenna is fabricated. The numerical and experiment results demonstrated that the proposed antenna satisfied the -10 dB impedance bandwidth requirement while simultaneously covering the WLAN and WiMAX bands. And characteristics of gain and radiation patterns are obtained for WLAN/WiMAX frequency bands.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.4
• /
• pp.213-217
• /
• 2014

In this paper, we designed monopole microstrip antenna for WLAN/WiMAX system. The monopole antenna is designed by FR-4 substrate with size is $30mm{\times}40mm$. The proposed antenna is based on a planar monopole design which cover WLAN and WiMAX frequency bands. To obtain the optimized parameters, we used the simulator, CST's Microwave Studio Program and found the parameters that greatly effect antenna characteristics. Using the obtained parameters, the antenna is designed. Thus the proposed antenna satisfied the -10 dB impedance bandwidth requirement while simultaneously covering the WLAN and WiMAX bands. And characteristics of gain and radiation patterns are obtained for WLAN/WiMAX frequency bands.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.11 no.3
• /
• pp.362-367
• /
• 1987

Cylinder pressure level is defined the value of sound pressure level derived from relations of pressure and frequency which are obtained Fourier series expansion of cylinder pressure. CPL is alone in general use in combustion analysis without regarding attenuation coefficient determined by engine structure because it is almost constant in various kinds of engines. Combustion pressure fluctuation and influence of CPL was investigated in this paper using Wiebe combustion function superposition th obtain the effect of premixed and diffusive combustion. The results are as follow. (1) Influence of combustion maximum pressure(P$\sub$max/) on CPL is correspond with total energy per cycle well. (2) P$\sub$max/, .DELTA.P$\sub$max/, (dp/d.theta.)$\sub$max/ and (d$\^$2/p/d.theta.$\^$2/)$\sub$max/ are very effective on CPL in the range of low frequency, mid-low frequency, mid-high frequency and high frequency respectively.

• Journal of Internet Computing and Services
• /
• v.16 no.6
• /
• pp.1-9
• /
• 2015

In this paper, we study the coexistence of typical radio access technologies (WiMAX, CDMA, WLAN) in heterogeneous networks. Although the radio accesses employ different frequency band, they can interfere with each other due to out-of- band emission. We compute the minimum adjacent channel interference ratio (ACIR) to satisfy the allowable level of interference, and the resulting minimum frequency separation (guard band) between interfering and victim system. We observe that WiMAX-WLAN coexistence and WiMAX-CDMA coexistence are feasible with at least 20 MHz and 15 MHz guard bands, respectively.

• Journal of the Korean Magnetics Society
• /
• v.7 no.1
• /
• pp.19-24
• /
• 1997

Composition and process conditions for low temperature sintered NiCuZn ferrites were investigated, so as to fabricate multilayered chip inductor. The$Fe_2O_3$ deficiency for low temperature sintering was decreased with NiO contents of NiCuZn ferrites. The permeability of NiCuZn ferrites can be controlled in the range of 12~562 with the variation of NiO and $Co_3O_4$ contents. The $Q_{max} $ frequency of NiCuZn ferrites was decreased from 50 MHz to 3 MHz linearly with permeability increase from 60 to 560. The relation between the $Q_{max}$ frequency(Y) and permeability(X) of NiCuZn ferrites was expressed with the following empirical equation, logY=4.2-1.4logX.

• ETRI Journal
• /
• v.33 no.6
• /
• pp.957-960
• /
• 2011

We present a fair and efficient solution for selfish readers with the Nash bargaining solution (NBS) to mitigate the effects of RFID frequency interference. We compare the NBS with a solution derived by the max log-sum scheme that maximizes total utility and show that for selfish and rational readers, the NBS brings success in bargaining on resource allocation between readers unlike the max log-sum scheme, although the NBS has less total payoff compared to the max log-sum scheme.

• Proceedings of the IEEK Conference
• /
• 2003.07b
• /
• pp.1053-1056
• /
• 2003

A distortion suppression technology for employing multiple inputs in 3n+1 type current mode Max circuit is proposed using the adjustment of transconductance. If the number of inputs in current mode Max circuit increases, the high frequency distortion in the output signal grows. In this paper, it has been disclosed that the distortion in the multiple input Max circuit is proportional to sum of parasitic capacitance in input terminals, to the derivative of the output signal and also to the inverse of transconductance of the common diode-connected transistor. The proposed idea is by employing as larger transconductance of the common diode-connected transistor as possible. The effectiveness of the proposed idea has been proved through the HSPICE simulation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.11A
• /
• pp.844-851
• /
• 2009

Handover is needed in multi-hop relay systems to support mobility. The main purpose of handover is to provide the continuous connection when a MS migrates from the air-interface of one BS to another air-interface provided by another BS. Especially the handover between different systems is essential to next generation network. Vertical Handover technology in Mobile WiMAX MMR system is very useful for operators to introduce to Mobile WiMAX system in an overlaid cell environment. This technology will be applied to technology which hands MRS(Mobile Relay Station) over to different systems for system performance enhancement in Ubiquitous environment overlaid between Micro ce11(Frequency 1,FA1) and Macro cell(Frequency 2,FA2). In this paper, FA1 and FA2 are used in order to perform Vertical Handover of MRS(Mobile Relay Station) according to suggested conditions. interferences from neighboring BS or other sectors of 6 macro cells surrounding center Macro cell are analyzed and throughputs are measured according to suggested conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.6
• /
• pp.125-132
• /
• 2023

To NP-complete 3-SAT problem, this paper proposes a O(nm) polynomial time algorithm, where n is the number of literals and m is the total frequency of all literals in equation f. Conventionally well-known DPLLs should perform O(2^𝑙) in the worst case by performing backtracking if they fail to find a solution in a brute-force search of a branch-and-bound for the number of literals 𝑙. DPLL forms the core of the SAT Solver by substituting true(T) or false(F) for a literal so that a clause containing the least frequency literal is true(T) and removing a clause containing that literal. Contrary to DPLL, the proposed algorithm selects a literal _max𝑙 with the maximum frequency and sets $_{\max}({\mid}l{\mid},{\mid}{\bar{l}}{\mid})=1$. It then deletes 𝑙∈c_i clause in addition to ${\bar{l}}$ from ${\bar{l}}{\in}c_i$ clause. Its test results on various k-SAT problems not only show that it performs less than existing DPLL algorithm, but prove its simplicity in satisfiability verification.