Earticle

This paper explores how to convert hierarchical syntactic structure to linear word order. Rather than taking the more popular ideas such as the head parameter hypothesis by Chomsky (1981) or the strict mapping hypothesis by Kayne (1994), we take the mapping parameter approach proposed by Kural (2005) which attributes typologically different word orders to different algorithms of mapping hierarchical structure onto linear strings. In particular, we show that the concept of preorder, inorder and postorder tree traversals in computer science can be employed as mapping algorithms to turn a universal base structure to VSO, SVO and SOV word orders. Furthermore, the tree traversal algorithms account for in-situ properties of wh-expressions and VP-internal subjects in languages like Korean, in addition to doing away with multiple applications of leftward movements needed in Kayne's (1994) system. We also demonstrate how the tree traversal algorithms can be properly designed and computer-implemented to yield relevant word orders in typologically different languages

RF power amplifier requires linearization in order to reduce adjacent channel interference. And most of the existing linearization algorithms assume that a PA has memory-less nonlinearity. But for the wider bandwidth signal, the memory effect of PA cannot be ignored. This paper investigates digital pre-distortion by use of a memory polynomial model which compensates for amplifier nonlinearity and memory effect. The look-up table based implementation scheme is used to reduce the computational complexity of the pre-distortion block. The linearization performance is demonstrated on wideband CDMA signal and class AB high power amplifier.

본 논문에서는 구동단의 IMD 특성과 최종단의 IMD 특성을 조절하여 선형성을 개선하는 방법에 대하여 제안을 하였다. WCDMA 4FA의 입력 신호를 사용하였을 때 평균 전력 50W에서 약 -48dBc@5MHz offset의 ACLR 특성을 얻었다. 제안된 역위상화 선형화 기법은 추가적인 선형회로 없이 구동 증폭단을 이용하여 전치왜곡 효과를 얻을 수 있었다. 이러한 점은 기존 analog predistortion 방식과 feedforward 방식의 단점을 보완하였음에 큰 의미를 가진다.

This paper proposes linearization technique that the linearity is improved by controlling IMD between the drive stage and the output stage. From the experimental results of W-CDMA 4FA input signal, this amplifier has ACLR of -48dBc@5MHz offset at 50W average power. Proposed linearization technique provides predistortion effect for using drive amplifier without additional circuit, which is the significant in this paper that it makes up for the weak point of analog predistortion method and feedforward method.

Of the core syntactic relations in UG, nothing is more gregarious than c-command. It plays a key role in at least three different domains: binding, linearization and movement. However, in terms of the Minimalist Program, it is desirable for c- command to be eliminated from linguistic theory. This paper explores the syntactic properties of c-command in the phenomena of binding, linearization and movement. I argue some advantages of the analysis without recourse to the c-command relation and examine their problems. The proposal of this study is to discuss the possibility of eliminating the c-command relation in each case

본 논문에서는 비선형 앰프를 선형화하는 LUT (look-up table)에 기반한 디지털 전치왜곡 알고리즘을 제안한다. 제안하는 방식은 기존 다항식 기반의 간접학습 방법을 이용하여 전력증폭기를 선형화하는 사후왜곡기를 먼저 구한 다음 이를 바탕으로 LUT 전치왜곡기를 구한다. 제안하는 기법에서는 기존 다항식 기법의 빠른 학습속도와 우수한 선형성능의 장점을 취하면서 많은 곱셈기로 인한 실시간 전치왜곡의 구현 복잡도를 LUT를 이용하여 낮추는 것이 장점이다. 제안하는 기법의 성능은 위성통신에 사용되는 실제 전력증폭기를 이용한 실험을 통해 확인한다. 구체적으로 약 8 GHz 대역에서 동작하는 광대역 TWTA (Travelling Wave Tube Amplifier)를 이용하여 제안하는 전치왜곡기법과 기존 다항식 전치왜곡 기를 비교한다. 실험결과 LUT의 크기가 64 이상이면 다항식 기법과 성능차이가 거의 없는 것을 확인할 수 있다. 제안하는 기법은 사용하는 곱셈의 개수가 1/10 수준에 불과하기 때문에 구현복잡도 측면에서 장점을 가진다.

This paper proposes a new LUT (look-up table) based digital predistortion technique to linearize non-linear power amplifiers. In the proposed method, a post-distorter is first found using the conventional polynomial based indirect-learning technique. Then, based on the post-predistorter, LUT predistorter is found. The proposed predistorter takes advantages of fast training speed and excellent linearization performance while mitigates the burden of real-time implementation complexity due to multiplications by using LUT. The performance of the proposed technique is examined through experiment with power amplifiers for satellite communications. Specifically, we compare the performances of the conventional polynomial predistorter and the proposed predistorter using 8 GHz band TWTA (Travelling Wave Tube Amplifier). According to the results, when the LUT size is over 16, both techniques shows almost the same performance. Since the proposed predistorter has a 10 times smaller multiplications, the proposed one has advantages in terms of implementation.

Kim, Jeong-Seok. 2015. Quantifier Sharing. Korean Journal of Linguistics, 40-1, 67-85. Since McCawley (1993), determiner sharing constructions have been in the spotlight. What is essential is that determiner sharing depends on Gapping and the shared determiner must be conjunct-initial. We first observe that quantifier sharing is possible in Korean. Following Kim (2011), we then argue that shared constituents can be linearized if they undergo movement out of the coordination site, which makes the shared position unpronounced. Since the shared position is not regulated by the LCA after movement, it causes no problem for PF linearization. (Korea University)

In this paper, we consider the dynamical model of a class of underactuated systems. By combination of the partial fedback linearization and Yamada’s global linearization, we deduced a global approximate linearization method for underactuated systems. By using this method, the dynamical equations can be transformed into an state eqution that is expressed as a pseudolinear term with Brunovsky canonical form plus a high order nonlinear term, where the nonlinear term is high order on the equilibrium manifold of the system. By standard nonlinear feedback method, the system is transformed into the sum of a stable linear term and a high order nonlinear term. Take proper feedforward value as the input to reduce the influence of the nonlinear term to the system and thus the underactuated system can be regulated. This method is applied to the ball and beam system and simulation results show that the proposed approximate linearization method is effective for setpoint control.

Microbial fuel cells (MFCs) are bioelectrochemical devices which degrade organic substrate with help of consortia of micro-organisms as catalyst for electrogenesis in their anode; to produce electrical current. MFC power output is a function of many operating factors such as pH, temperature, loading rate, flow rate, and electrical load, which would define its state. However, the work presented here seeks to identify dynamic cause and effect relationships between key parameters and piecewise linearise the MFC process. A sandwich-type MFC was subjected to a varying electrical load of various Pseudo-Random and step inputs, while observing the MFC voltage. Nonlinear behaviour was inferred from assumed piecewise linearised first order dynamic responses, at different operating points. The time constants increased from 0.5 s with PRBS loading of 100 Ω – 150 Ω, to 6.2 s at 950 Ω – 1 kΩ; although steady state gain varied little, (0.12 mV Ω-1 to 0.20 mV Ω-1). This suggests that the MFC’s non-linear behaviour dependent on operating conditions may be adequately represented by a series of linear models. System Identification suggested that linear 4rd order ARX models had the best fit. However, reasonable prediction was observed using piecewise linearised first order models. The models could be used to design and optimize controllers to regulate power and/or voltage generation.

This paper presents the non-linear control of an induction motor (IM). The objective of nonlinear control is to can control separately flux and the speed, several techniques of control are used for (IM), The technique of control oriented flux (FOC) whichpermits the decoupling between input and output variables, so (IM) is assimilate to continuous current motor , this method has a problem is how exactly oriented the axis d on the flux .However, feedback linearization amounts to cancelling the nonlinearities in a nonlinear system so that the closed- loop (CL) dynamics is in a linear form . A goal of feedback linearizationis to can controlled separately flux and the speed ,the motor model is strongly nonlinear then it’s composed to the autonomous and mono- variables too under systems so every under system presented an independence loop of control for each variables is given . We proposed the MRAS (system adaptive reference model) for speed and rotor fluxobserver.

This paper presents two modifications of the gpICA (geometric post non-linear independent component analysis) algorithm. gpICA algorithm is a novel method to solve the PNL (Post non-linear) scheme. We propose these modifications to improve the mean squared error, the correlation of the recovered signals and algorithm reliability . The first improvement, called compensation, takes advantage of the implicit information given by the point to be linearized. On the other hand, while the original gpICA algorithm uses two sets of two points to make an update, our second modification uses two sets of four points. We present experimental results which validates the effectiveness of each modification. The PNL applications can be seen in sensor array processing, digital satellite, microwave communications, biological systems and nonlinear blind source separation tasks. gpICA can recover the original sources of a nonlinear mixture, unlike some of the other nonlinear BSS algorithms, it does not require any assumption on the distribution of the input signals.

The new generation mobile communication systems are very sensitive to the nonlinearities in their transmitting paths. The power amplifier is a key component which generates the nonlinear distortions. Power amplifier linearization techniques are very important to reduce the distortion of the transmitted signal and the adjacent band interference of users. As its facility of implementation, adaptive ability and high efficiency, the pre-distortion technology becomes the first choice to minimize the nonlinear distortions. In this paper, a new technique, based on the pre-distortion principle for linearizing a power amplifier, which is modeled by a Wiener model is proposed. The Wiener model is used to take into account the nonlinearities and the memory effects of the power amplifier. We also propose an efficient and original method for extracting the parameters of the power amplifier’s Wiener Model. Simulation results have been provided for showing the performances of this technique.

Park, Myung-Kwan. 2010. Derivation via External Remerge and Linearization in ATB, RNR and PG Constructions of English. Korean Journal of Linguistics, 35-3, 601-622. This paper investigates the syntactic derivation and linearization of the ATB, RNR and PG constructions. These three constructions look similar, in that they are constituted of two clauses, and one displaced element at sentence-initial or final position binds two gaps within the clauses. However, we argue that the ATB and RNR constructions behave in almost identical ways, distinguishing themselves from the PG construction. More specifically, in the former two constructions, the ATB-moved or RNRed element is first displaced to the left or right edge of each conjunct clause, and then is conjoined together via External Remerge. As the two constructions are composed of two coordinate conjunct clauses, in the course of linearization the word order of each conjunct clause has to be parallel to its realization in the final output of larger ATB or RNR construction. In the PG construction, however, parallelism of this kind is not at work. Rather, the chain of the parasitic gap in the subordinate clause is linked via External Remerge to the chain of the real gap in the superordinate clause. And in the course of linearization a moved element tends to be pronounced at the target position rather the source position, without invoking any effect of parallelism. (Dongguk University) 조회수 1 추천수 0

Design a nonlinear controller for second order nonlinear uncertain dynamical systems (e.g., Internal Combustion Engine) is one of the most important challenging works. This paper focuses on the design of a robust backstepping adaptive feedback linearization controller (FLC) for internal combustion (IC) engine in presence of uncertainties. In order to provide high performance nonlinear methodology, feedback linearization controller is selected. Pure feedback linearization controller can be used to control of partly unknown nonlinear dynamic parameters of IC engine. In order to solve the uncertain nonlinear dynamic parameters, implement easily and avoid mathematical model base controller, Mamdani’s performance/error-based fuzzy logic methodology with two inputs and one output and 49 rules is applied to pure feedback linearization controller. The results demonstrate that the error-based fuzzy feedback linearization controller is a model-free controllers which works well in certain and partly uncertain system. Pure feedback linearization controller and error-based feedback linearization like controller with have difficulty in handling unstructured model uncertainties. To solve this problem applied backstepping-based tuning method to error-based fuzzy feedback linearization controller for adjusting the feedback linearization controller gain ( ). This controller has acceptable performance in presence of uncertainty (e.g., overshoot=1%, rise time=0.48 second, steady state error = 1.3e-9 and RMS error=1.8e-11).