A new framework for two loop disturbance rejection control

In this paper, a new framework of a two loop disturbance rejection control and its design methodology are proposed. The framework consists of a robust internal-loop compensator (RIC) to eliminate disturbances and an external-loop controller to achieve nominal control performance. As the main contribution of this paper, we define the design problem of the RIC as a regulation control problem, then show that this new definition with the RIC structure provides more design flexibility and less implementation constraints, which allows us to design the RIC aggressively against a specific disturbance. This is verified through a comparative structural analysis with a disturbance observer (DOB) and an adaptive robust control (ARC). Two design examples of the RIC are given, along with practical issues that should be considered in the design procedure. The proposed framework is demonstrated by simulations and experiments.     

Development of a scale for fantasy state in digital games

Digital games appear to motivate players intrinsically. Of various game features, fantasy in particularly plays a crucial role in enhancing motivation and is a key factor in immersion in gameplay. As with its inherent value, fantasy also plays a vital role in distinguishing digital games itself from other media. Despite its significance, fantasy has received little attention, and this concept is still ambiguous to define with any certainty. This study thus aims to create a framework to explore a dimension of fantasy and to develop a scale to measure a state of fantasy in digital games. As a result, four factors were extracted, which were ‘identification’, ‘imagination’, ‘analogy’, and ‘satisfaction’, to account for fantasy state in digital gameplay. Based on these factors, a fantasy scale in digital games (FSDGs) included 16 items was developed.     

Personal driving diary: Automated recognition of driving events from first-person videos

In this paper, we introduce the concept of personal driving diary. A personal driving diary is a multimedia archive of a person’s daily driving experience, describing important driving events of the user with annotated videos. This paper presents an automated system that constructs such multimedia diary by analyzing videos obtained from a vehicle-mounted camera. The proposed system recognizes important interactions between the driving vehicle and the other actors in videos (e.g., accident, overtaking, etc.), and labels them together with its contextual knowledge on the vehicle (e.g., mean velocity) to construct an event log. A decision tree based activity recognizer is designed, detecting driving events of vehicles and pedestrians from the first-person view videos by analyzing their trajectories and spatio-temporal relationships. The constructed diary enables efficient searching and event-based browsing of video clips, which helps the users when retrieving videos of dangerous situations. Our experiment confirms that the proposed system reliably generates driving diaries by annotating the vehicle events learned from training examples.     

Schemes generating entangled states and entanglement swapping between photons and three-level atoms inside optical cavities for quantum communication

We propose quantum information processing schemes based on cavity quantum electrodynamics (QED) for quantum communication. First, to generate entangled states (Bell and Greenberger–Horne–Zeilinger [GHZ] states) between flying photons and three-level atoms inside optical cavities, we utilize a controlled phase flip (CPF) gate that can be implemented via cavity QED). Subsequently, we present an entanglement swapping scheme that can be realized using single-qubit measurements and CPF gates via optical cavities. These schemes can be directly applied to construct an entanglement channel for a communication system between two users. Consequently, it is possible for the trust center, having quantum nodes, to accomplish the linked channel (entanglement channel) between the two separate long-distance users via the distribution of Bell states and entanglement swapping. Furthermore, in our schemes, the main physical component is the CPF gate between the photons and the three-level atoms in cavity QED, which is feasible in practice. Thus, our schemes can be experimentally realized with current technology.     

Numerical stability of symmetric solitary-wave-like waves of a two-layer fluid—Forced modified KdV equation

Forced internal waves at the interface of a two-layer incompressible fluid in a two-dimensional domain with rigid horizontal boundaries are studied. The lower boundary is assumed to have a small obstruction. We derive a time-dependent forced modified KdV equation when the KdV theory fails and study the stabilities of four types of symmetric time-independent solitary-wave-like solutions numerically.     

Closed-form forward kinematics solutions of a 4-DOF parallel robot

It is well known that the forward kinematics of parallel robots is a very difficult problem. Closed-form forward kinematics solutions have been reported only to a few special classes of parallel robots. This paper presents closed-form forward kinematics solutions of a 4-DOF parallel robot H4. A 16th order polynomial in a single variable is derived to solve the forward kinematics of the H4. The 16 roots of the polynomial lead to at most 16 different forward kinematics solutions. A numerical verification is also presented.     

Monitoring skin condition using life activities on the SNS user documents

Multimedia Tools and Applications - Social networks are not new to the IT landscape. Starting from bulletin boards and chat rooms, they have evolved to include desktop and mobile device...     

Correction to: A comprehensive evaluation of availability and operational cost for a virtualized server system using stochastic reward nets

The Journal of Supercomputing - The section “Acknowledgement” was incorrect in the original article. The correct section “Acknowledgement” is given below.     

Direct Numerical Simulation of Turbulent Flow in a Square Duct: Analysis of Secondary Flows

A direct numerical simulation of turbulent flow in a square duct was performed for a Reynolds number based on bulk streamwise velocity and duct height equal to 4,440. The mechanism by which secondary flows are generated in a square duct was investigated. Two counterrotating secondary flows occur around the duct corner. These secondary flows were found to play a key role in momentum transfer between the corner and center of the duct. A conditional quadrant analysis was performed in the local maximum and minimum regions of the wall shear stress in order to characterize the pattern of the mean secondary flows.     

Development and optimal design of a HDD spindle motor with pulling magnet to reduce electrical loss

A conventional hard disk drive (HDD) spindle motor has a pulling plate to generate the axial magnetic force. However, the pulling plate consumes significant amount of iron loss due to the alternating magnetic field on the pulling plate. We propose the new design of a HDD spindle motor with pulling magnet to generate the pre-load as well as to eliminate the iron loss of the pulling plate. We also develop an optimal design methodology to minimize iron and copper losses from the spindle motor of a computer HDD while maintaining the same level of torque ripple and pulling force. The new design is optimized by the developed optimal design methodology. A metamodel is constructed from the three-dimensional finite element analysis of the magnetic field and the meta-modeling techniques, and the accuracies of the metamodels are discussed. The proposed optimal design problem is solved by the progressive quadratic approximation method. The proposed design reduces the electrical loss of the HDD spindle motor by 30.42?% while maintaining the same level of torque ripple and pulling force.