The characteristics of laser-induced breakdown spectroscopy (LIBS) such as short measurement time and no sample preparation provide clear advantages over other analytical techniques for rapid elemental analysis at manufacturing sites where the composition of products need to be determined in real-time for process monitoring or quality control. Thin film solar cells based on CuIn<sub>1-x</sub>Ga<sub>x</sub>Se<sub>2</sub> (CIGS), polycrystalline compound semiconductor material, have unique advantages of high efficiency (>20%), long-term stability, and low manufacturing cost over other types of solar cell. The electrical and optical properties of the thin CIGS films are closely related to the concentration ratios among its major constituent elements Cu, In, Ga and Se such as Ga/(Ga + In) and Cu/(Ga + In), and thus an accurate measurement of the composition of CIGS thin films has been an issue among CIGS solar cell researchers, requiring a fast and reliable technique for composition analysis. This paper presents the results of nanosecond (ns) and femtosecond (fs) laser based LIBS analysis of thin CIGS films. The critical issues for LIBS analysis of CIGS thin films such are discussed in comparison with ns- and fs-LIBS measurement results. The calibration of LIBS signal intensity ratios with respect to reference concentration data is carried out and the results of optimal line selection for LIBS analysis, depth profiling capability, and reproducibility are discussed.
Network delay in haptic-based CVEs (collaborative virtual environments) severely deteriorates the haptic interaction quality (e.g., larger force feedback than real). In order to compensate this delay effect, existing studies dynamically change spring and damper coefficients according to the network delay. However, it is difficult to choose proper coefficients to offset the delay effect by precisely reflecting virtual object characteristics. In this paper, a new delay-compensation scheme based on the force feedback prediction is proposed to improve the force feedback experience. By predicting the virtual object movements and force feedback, the proposed scheme in client side provides timely force feedback to a user. Then, it gradually converges to real (but delayed) information from the server in order to maintain the consistency of virtual environment. According to the experiment results, the proposed scheme can improve the haptic interaction quality by providing more realistic force feedback similar to that of no network delay.
This paper proposes a prototype realization of multi-view HD video transport system with synchronized multiplexing
over IP networks. The proposed synchronized multiplexing considers the synchronization during video
acquisition and the multiplexing for the interactive view-selection during transport. For the synchronized acquisition
from multiple HDV camcoders through IEEE 1394 interface, we estimate the timeline differences among
MPEG-2 compressed video streams by using global time of network between the cameras and a server and correct
timelines of video streams by changing the timestamp of the MPEG-2 system stream. Also, we multiplex a selected
number of acquired HD views at the MPEG-2 TS (transport stream) level for the interactive view-selection
during transport. Thus, with the proposed synchronized multiplexing scheme, we can display synchronized HD
In this paper, we explain two transport-related experimental results for networked haptic CVEs (collaborative
virtual environments). The first set of experiments evaluate the performance changes in terms of QoE (quality
of experience) with the haptic-based CVEs under different network settings. The evaluation results are then
used to define the minimum networking requirements for CVEs with force-feedback haptic interface. The second
experiments verify whether the existing haptics-specialized transport protocols can satisfy the networking QoE
requirements for the networked haptic CVEs. The results will be used to suggest in design guidelines for an
effective transport protocol for this highly-interactive (i.e., extremely low-delay latency at up to 1 kHz processing
cycle) haptic CVEs over the delay-crippled Internet.
In this paper, we propose a design of multi-view stereoscopic HD video transmission system based on MPEG-21 Digital Item Adaptation (DIA). It focuses on the compatibility and scalability to meet various user preferences and terminal capabilities. There exist a large variety of multi-view 3D HD video types according to the methods for acquisition, display, and processing. By following the MPEG-21 DIA framework, the multi-view stereoscopic HD video is adapted according to user feedback. A user can be served multi-view stereoscopic video which corresponds with his or her preferences and terminal capabilities. In our preliminary prototype, we verify that the proposed design can support two deferent types of display device (stereoscopic and auto-stereoscopic) and switching viewpoints between two available viewpoints.
In this paper, we design and implement a prototype system with an adaptive intra-media synchronization scheme for haptic interactions in distributed virtual environments (DVEs). In order to interact with haptic interfaces in the DVEs, we require a stringent level of QoS service from the network. Especially, network delay jitter and packet loss over the Internet may seriously degrade the output quality of haptic media in the DVEs. The proposed system model consists of three layers (application, synchronization, and network) to support haptic interactions over time-varying IP networks. The intra-media synchronization scheme implemented in the system controls buffering time and transmission rate to enhance the QoS of networked haptic interactions. To demonstrate usefulness of the proposed scheme, we simulate it by using NS-2 simulator and implement simple haptic-based
DVEs. According to the simulation results, the proposed scheme provides more stable playout of haptic data under network delay jitter. Moreover, when lots of clients are participating in the DVEs, it can decrease the transmission rate of haptic data so that we can get smaller network delay. According to the experiment results, the proposed scheme can be applied to the real DVEs under network delay jitter.