9976676
Considerations for linking seatpan and backrest angles
Modern ergonomic chairs typically have several dimensions that can be adjusted independently of one another. Finding a desirable setting for any one dimension can depend on how other dimensions are set, thereby confronting users with a significant control problem. One design strategy for dealing with this problem has been to link changes in seatpan and backrest angles in some ratio, such that a one‐degree change in seatpan angle is associated with a two‐ or three‐degree change in backrest angle. However, there is no evidence to justify the choice of a particular ratio. This article presents data that addresses this issue. Subjects, performing either an entry or verification task, could adjust the chair to any position. Backrest and seatpan angles were plotted over time and analyzed using both graphical and statistical methods. The resulting scatter plots do not support the industry standard, 1:2 or 1:3 ratio, of changes in seatpan to backrest angles. The possibility of a variable linkage is discussed; how...
2497607
Comparative Hypertext Approaches to Ergonomic Training
Training users to utilize ergonomic information effectively in workplace design requires the application and integration of multiple sources of information (e.g., interdependent criteria for furniture adjustability and keyboard/display location). To aid users in coping with such a complex task, the use of hypertext representation of complex documents is increasing. However, when searching in a complex hypertext application, users may experience navigation disorientation and cognitive overload. This study examined the relative effectiveness of a semantic relationship for a hypertext interface, and the relationship between semantic representations and complexity of search task. The goal was to design a more effective hypertext interface for complex documents in support of users' problem solving.
23372402
Information Concept Lattice and Its Reductions
In this paper, the combination of formal concept analysis and rough set theory is considered. The notion of information concept lattice is presented and some properties are given. We present the reduction theory of information concept lattice and obtain the reduction method. Information concept lattice is compared with rough set theory and concept lattice.
28123449
Zum Einsatzpotenzial von Wetterderivaten in der Landwirtschaft - dargestellt am Beispiel einer Niederschlagsoption
In diesem Beitrag wird am Beispiel eines getreideproduzierenden Betriebes in Brandenburg unter Verwendung von realen Wetterdaten der risikomindernde Effekt durch den Einsatz von Niederschlagsoptionen analysiert. Es zeigt sich, dass Niederschlagsoptionen nur dann effektiv eingesetzt werden konnen, wenn sich die Referenzwetterstation in unmittelbarer Nahe des Ortes der landwirtschaftlichen Produktion befindet.
17935039
Data manipulation techniques to reduce phase change memory write energy
Due to its great scalability potential, phase change memory has become a topic of great current interest. However, high write energy consumption appears to be one of the biggest challenges to be tackled before phase change memory can be adopted as a mainstream memory technology. This paper presents architecture level technique to reduce phase change memory write energy consumption through data manipulations. Motivated by the fact that phase change memory read incurs much less energy than write and write of different value to a phase change memory cell incurs largely different energy, we present two memory write data manipulation techniques that can effectively reduce the overall memory write energy consumption. Their effectiveness has been demonstrated based on mathematical analysis and computer system simulation using phase change memory as the main memory in the computer memory hierarchy. Significant energy savings with up to more than 60% have been shown over a wide range of computer system benchmarks.
7423569
Global Analysis of Stochastic bifurcation in Duffing System
Stochastic bifurcation of a Duffing system subject to a combination of a deterministic harmonic excitation and a white noise excitation is studied in detail by the generalized cell mapping method using digraph. It is found that under certain conditions there exist two stable invariant sets in the phase space, associated with the randomly perturbed steady-state motions, which may be called stochastic attractors. Each attractor owns its attractive basin, and the attractive basins are separated by boundaries. Along with attractors there also exists an unstable invariant set, which might be called a stochastic saddle as well, and stochastic bifurcation always occurs when a stochastic attractor collides with a stochastic saddle. As an alternative definition, stochastic bifurcation may be defined as a sudden change in character of a stochastic attractor when the bifurcation parameter of the system passes through a critical value. This definition applies equally well either to randomly perturbed motions, or to p...
9571243
trNon-greedy active learning for text categorization using convex ansductive experimental design
In this paper we propose a non-greedy active learning method for text categorization using least-squares support vector machines (LSSVM). Our work is based on transductive experimental design (TED), an active learning formulation that effectively explores the information of unlabeled data. Despite its appealing properties, the optimization problem is however NP-hard and thus--like most of other active learning methods--a greedy sequential strategy to select one data example after another was suggested to find a suboptimum. In this paper we formulate the problem into a continuous optimization problem and prove its convexity, meaning that a set of data examples can be selected with a guarantee of global optimum. We also develop an iterative algorithm to efficiently solve the optimization problem, which turns out to be very easy-to-implement. Our text categorization experiments on two text corpora empirically demonstrated that the new active learning algorithm outperforms the sequential greedy algorithm, and is promising for active text categorization applications.