We previously proposed an iterative decision-directed channel estimation and inter-carrier interference (ICI) cancellation (IDD-ICICan) technique based on estimating the diagonal and off-diagonal vectors of the channel frequency response matrix (CFRM) of a double-selective fading channel. In this paper, we first present some new theoretical analysis that is missing from the previous investigation, including the correlation property within each off-diagonal vectors of the CFRM, and the derivation of the constant scaling relation between different off-diagonal vectors. An enhanced IDD-ICICan (EIDD-ICICan) is then proposed for better performance. At last, we report the simulation performance of a Digital Video Broadcasting (DVB) receiver equipped with the EIDD-ICICan, demonstrating its robust performance even in very fast fading channels. In addition, we show that the superior performance is achieved with well affordable complexity.
Handheld Perspective Corrected Displays (HPCDs) can create the feeling of holding a virtual 3D object. They offer a direct interaction that is isomorphic to the manipulation of physical objects. This illusion depends on the ability to provide a natural visuomotor coupling. High performances systems are thus required to evaluate the fundamental merits of HPCDs. We built a spherical HPCD using external projection. The system offers a lightweight wireless seamless display with head-coupled stereo, robust tracking, and low latency. We compared users' performances with this HPCD and two other interactions that used a fixed planar display and either a touchpad or the spherical display as an indirect input. The task involved the inspection of complex virtual 3D puzzles. Physical puzzles were also tested as references. Contrary to expectations, all virtual interactions were found to be more efficient than a more "natural" physical puzzle. The HPCD yielded lower performances than the touchpad. This study indicates that the object examination task did not benefit from the accurate and precise rotations offered by the HPCD, but benefited from the high C/D gain of the touchpad.
In a shared telecommunications medium such as the Eureka 147 Digital Audio Broadcasting (DAB) system, we expect that available bandwidth will be optimally allocated to different users. This paper proposes optimal bandwidth allocation by use of statistical multiplexing that both service providers and multiplex operators can benefit from. Moreover, an auditory-based objective measure (i.e., ITU-R PEAQ) has been employed to make sure that the encoded audio materials maintain ¿broadcast quality¿. In our simulations of statistical multiplexing of five different ¿broadcast quality¿ radio programs, we show that a variable bit rate (VBR) stream with an average bit rate of 192 kbps could be saved as extra bandwidth in DAB to create new services. We also show that this VBR stream provides at least 112 kbps of extra capacity 98.5% of the time. The extra bandwidth can be used to transmit new audio programs, data or any side information to augment the radio listening experience.
BACKGROUND: The yield of white blood cells (WBCs) extracted from whole‐blood leukoreduction filters can be affected by the storage conditions and delay before filtration. Platelets (PLTs) collected with apheresis instruments (Trima Accel, Gambro BCT) are leukoreduced during the procedure on a fluidized particle bed in a leukoreduction chamber (LRS chamber). In this report, the residual cell content of these LRS chambers was characterized to determine whether it would be a valuable source of viable human blood cells. STUDY DESIGN AND METHODS: The content of LRS chambers was eluted by gravity, and peripheral blood mononuclear cells (PBMNCs) were purified on a Ficoll‐Paque gradient. Analyses were performed before and after freezing. Proportions of CD3+, CD14+, CD16+, CD19+, CD34+, and CD45+ cells were determined by flow cytometry. The frequency of T cells expressing CD4, CD8, and CD27 and of B cells expressing immunoglobulin G (IgG), IgM, and CD27 was also determined. RESULTS: LRS chambers held approximately 10 9 CD45+ cells representing the normal proportions of CD3+, CD14+, CD16+, and CD19+ cell populations of PBMNCs. A small fraction of these CD45+ cells were CD34+CD38+ cells (0.3 ± 0.2%). The viability of these cells, measured before and after freezing, was more than 95 percent. CONCLUSION: The residual cell content of Trima Accel LRS chambers recovered after PLT collection is a good source of viable monocytes and lymphocytes. These PBMNCs, containing CD3+, CD14+, CD16+, CD19+, and CD34+ cells can be frozen to prepare cell banks, which opens new avenues for utilization in several physiologic studies or even in cellular therapy applications.
