The path precompensation method for flexible arm robot

This paper constructed a closed loop path precompensation method for a flexible arm robot. A torque computation method taking care of the elastic arm deformation was first proposed and discussed. A concept of partial deformation compensation was subsequently proposed to improve the torque profiles and the trajectory fidelity. The advantage of this concept was first shown by examples of planar trajectory. After the construction of the closed-loop path precompensation method for a flexible arm, the torque method and partial deformation compensation were incorporated to track the spatial trajectory. Numerical simulations were given to show the usefulness of the proposed concept and method.     

Thermal, micro-structural, and electrical properties of a La1−x Sr x Mn0.85Fe0.05Co0.05Ni0.05O3+δ (x = 0–0.4 mole) cathode system

The oxygen stoichiometry, thermal expansion, morphology, and electrical conductivity of a co-doped perovskitetype cathode system, La_1?x Sr _x Mn_0.85Fe_0.05Co_0.05Ni_0.05O_3+ä (x = 0–0.4 mole), are studied for intermediate-temperature solid oxide fuel cell applications. Sr²⁺-doping led to a decrease in the unit cell volume, oxygen stoichiometry, particle size, and activation energy, and an increase in the coefficient of thermal expansion and electrical conductivity. The sample with x = 0.3 mole exhibited four to five fold weight loss with respect to La_0.75Sr_0.25MnO_3+δ at an intermediate temperature range and suggested the availability of a large number of oxygen vacancies due to a co-doping effect. This sample also showed sufficiently high electrical conductivity (～76 S cm^?1) at 650 °C, a low activation energy (～0.15 eV), and a coefficient of thermal expansion (～12.1 × 10^?6 °C^?1) comparable to those of the adjacent components and submicron sized particles. The experimental results are explained using defect models.     

The Relationships between Students' Conceptions of Learning Engineering and their Preferences for Classroom and Laboratory Learning Environments

This study developed a survey entitled Conceptions of Learning Engineering (CLE), to elicit undergraduate engineering students' conceptions of learning engineering. The reliability and validity of the CLE survey were confirmed through a factor analysis of 321 responses of undergraduate students majoring in electrical engineering. A series of ANOVA analyses revealed that students who preferred a classroom setting tended to conceptualize learning engineering as “testing” and “calculating and practicing,” whereas students who preferred a laboratory setting expressed conceptions of learning engineering as “increasing one's knowledge,” “applying,” “understanding,” and “seeing in a new way.” A further analysis of student essays suggested that learning environments which are student‐centered, peer‐interactive, and teacher‐facilitated help engineering students develop more fruitful conceptions of learning engineering.     

A quadratic time algorithm to maximize the number of just-in-time jobs on identical parallel machines

In this paper, we study a scheduling problem on identical parallel machines, in which a processing time and a due date are given for each job, and the objective is to maximize the number of just-in-time jobs. A job is called just-in-time if it is completed exactly on its due date. We discuss the known results, show that a recently published greedy algorithm for this problem is incorrect, and present a new quadratic time algorithm which solves the problem.     

Limiting negations in bounded-depth circuits: An extension of Markov's theorem

A theorem of Markov shows the necessary and sufficient number of negations for computing an arbitrary collection of Boolean functions. In this paper, we consider a class of bounded-depth circuits, in which each gate computes an arbitrary monotone Boolean function or its negation. We show tight bounds on the number of negations for computing an arbitrary collection of Boolean functions when such a class of circuits is under consideration.     

基于良序子集的最近邻垄行图像识别算法

根据田间作物垄点像素矩阵特点,基于行向量目标像素良序子集,先进行垄点子集预处理,然后运用最近邻判别准则搜寻每个垄点像素的最近邻点。通过设置最近邻搜索方向角和最近邻阈值,对断垄和较大面积的杂草等噪声影响进行控制。实验结果表明,与传统的最近邻算法比较,该算法的准确性和鲁棒性均得到提高,时间复杂度较小,对农田视觉导航实际应用有一定价值。     

Comparable Performance Measurement System for Construction Companies

The construction industry has mainly relied on financially focused performance measurements, and studies on performance measurement systems (PMSs) have been carried out at the project level. However, recently, the demand for performance evaluation and management at the company level has increased. A few previous efforts have aimed to develop a conceptual framework for company performance, but there have been few follow-up studies. From this perspective, we have developed an implementation model and practical methodology to measure and compare the performance of construction companies. First, our thorough qualitative and quantitative analysis was used to develop a set of indicators for performance measurement, and an analysis of the relative weightings of the indicators was carried out. Second, we calculated the performance score of construction companies using a study of 34 Korean construction companies. Finally, we carried out a performance evaluation and system analysis using the calculated performance scores and identified practical issues for the implementation of our PMS. Using the results of our analytical processes identified in this work, further research is suggested.     

Effects of boron and heat treatment on structure of dual-phase Ti-TiC

Anin situ method was developed to fabricate a two-phase mixture of titanium carbide in a titanium matrix by solidification from a titanium-carbon melt. The solidified morphology consisted of three-dimensional TiC dendrites in a titanium matrix. The secondary dendrite arm spacing was found to be influenced by the presence of boron. The structure and microhardness of the components as a function of boron content and heat-treatment procedure were determined. Heat treatment plays a major role in the structure while the effect of boron is minimal. Results from X-ray diffraction analysis indicate that the solidified carbide is very rich in vacancies in the carbon sublattice. Annealing leads to a redistribution of the titanium atoms to occupy some of the vacant carbon sites. This thermal redistribution effect results in a dramatic decrease in the hardness of the carbides. The lattice parameter measurement supports the above structure evolution.     

Introduction to the Special Issue on Empirical Evaluation of User Models and User Modeling Systems

User Modeling and User-Adapted Interaction -