• 대한수학회논문집
• /
• 제26권4호
• /
• pp.585-589
• /
• 2011

Using algebraic methods, we prove that every Jordan (${\varphi},{\psi}$derivation is a (${\varphi},{\psi}$derivation under certain conditions. In particular, we conclude that every Jordan ${\theta}$-derivation is a ${\theta}$-derivatio.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제10권4호
• /
• pp.207-215
• /
• 2003

Let R be a prime ring with characteristic different from two and let $\theta,\varphi,\sigma,\tau$ be the automorphisms of R. Let d : $R{\rightarrow}R$ be a nonzero ($\theta,\varphi$)-derivation. We prove the following results: (i) if $a{\in}R$ and [d(R), a]$_{{\theta}o{\sigma},{\varphi}o{\tau}}$=0, then $\sigma(a)\;+\;\tau(a)\;\in\;Z$, the center of R, (ii) if $d([R,a]_{\sigma,\;\tau)\;=\;0,\;then\;\sigma(a)\;+\;\tau(a)\;\in\;Z$, (iii) if $[ad(x),\;x]_{\sigma,\;\tau}\;=\;0;for\;all\;x\;\in\;RE$, then a = 0 or R is commutative.

• 한국영어학회지:영어학
• /
• 제2권2호
• /
• pp.207-226
• /
• 2002

In this paper we provide an alternative explanation for there construction, by assuming that the expletive there (EXPL) has independently uninterpretable Case feature as well as u[person], not as being pied-pipied with $\varphi$-feature. If EXPL has only u[person], we could analyse incorrectly some there constructions, including an embedded infinitive clause: by Chomsky (1998, 1999) in the construction, EXPL is ‘frozen’ and cannot participate in the computation of higher. As a result, we could predict incorrectly that the derivation is crashed. But if EXPL has two uninterpretable features, u[person] and u[Case], we could predict correctly that the derivation is converged: the u[person] of EXPL is deleted under Matching/Agree with $T_{def}$; still, the undeleted u[Case] of EXPL is activating; so EXPL can be raised to [SPEC, T] to satisfy the EPP-feature of matrix T.

• Journal of electromagnetic engineering and science
• /
• 제6권3호
• /
• pp.182-188
• /
• 2006

Orthogonal frequency division multiplexing(OFDM) is very useful for the wireless communication system. However, OFDM is very sensitive to the radio frequency impairments. One of the most important major impairments is the IQ imbalance between in-phase(l) and quadrature(Q) branches in the up and down-conversion. IQ imbalance can be divided into phase and amplitude imbalances. These imbalances make constellation of signal to expand and rotate. The performance of system is severely degraded. In this paper, a closed-form for the bit error probability of the OFDM signal in IQ imbalance environment is derived in terms of the function of phase and amplitude imbalance parameters. So, it will be convenient and useful to evaluate the performance of OFDM communication system with IQ imbalance. It is confirmed that computer simulation results closely match with the results of the analytical derivation. When phase imbalance $\varphi=20^{\circ}$, amplitude imbalance $\varepsilon=0.1$; 0.3; 0.4; 0.5, BER at $10^{-5}$ is severely degraded by 1.8 dB, 3.12 dB, 4.72, and 8.44 dB, respectively.