Joint Multi-Cell Resource Allocation Using Pure Binary-Integer Programming for LTE Uplink

Due to high system capacity requirement, 3GPP Long Term Evolution (LTE) is likely to adopt frequency reuse factor 1 at the cost of suffering severe inter-cell interference (ICI). One of combating ICI strategies is network cooperation of resource allocation (RA). For LTE uplink RA, requiring all the subcarriers to be allocated adjacently complicates the RA problem greatly. This paper investigates the joint multi-cell RA problem for LTE uplink. We model the uplink RA and ICI mitigation problem using pure binary-integer programming (BIP), with integrative consideration of all users' channel state information (CSI). The advantage of the pure BIP model is that it can be solved by branch-and-bound search (BBS) algorithm or other BIP solving algorithms, rather than resorting to exhaustive search. The system-level simulation results show that it yields 14.83% and 22.13% gains over single-cell optimal RA in average spectrum efficiency and 5th percentile of user throughput, respectively.Comment: Accepted to IEEE Vehicular Technology Conference (VTC Spring), Seoul, Korea, May, 201

HUMAN MICROVASCULATURE FABRICATION USING THERMAL INKJET PRINTING TECHNOLOGY

The current tissue engineering paradigm is that successfully engineered thick tissues must include vasculature. As biological approaches alone such as VGEF have fallen short of their promises, one may look for an engineering approach to build microvasculature. With the advent of cell printing, one may be able to build precise human microvasculature with suitable bio-ink. Human Microvascular Endothelial Cells (HMVEC) and fibrin were studied as bio-ink for microvasculature construction. Endothelial cells are the only cells to compose the human capillaries and also the major cells of blood vessel intima layer. Fibrin has been already widely recognized as tissue engineering scaffold for vasculature and other cells, including skeleton/smooth muscle cells and chondrocytes. In our study, we comprehensively studied changes in heat shock protein expression and cell membrane morphogenesis in printed mammalian cells with thermal inkjet printers. The heat shock protein expression of the printed cells has minor difference between the untreated cells and lower than manually heated cells. The cell membrane of printed cells developed pores which allow small molecules such as propidium iodide and dextran molecules (up to 70kD) to pass. We then precisely fabricated micron-sized fibrin channels using a drop-on-demand polymerization. When printing HMVEC cells in conjunction with the fibrin, we found the cells aligned themselves inside the channels and proliferated to form confluent linings. The 3D tubular structure was also found in the printed patterns. We conclude that cell printing technology can be used for precise cell seeding in tissue engineering fabrication with minor effect and damages to the printed mammalian cells

Investigations of supernovae and supernova remnants in the era of SKA

Two main physical mechanisms are used to explain supernova explosions: thermonuclear explosion of a white dwarf(Type Ia) and core collapse of a massive star (Type II and Type Ib/Ic). Type Ia supernovae serve as distance indicators that led to the discovery of the accelerating expansion of the Universe. The exact nature of their progenitor systems however remain unclear. Radio emission from the interaction between the explosion shock front and its surrounding CSM or ISM provides an important probe into the progenitor star's last evolutionary stage. No radio emission has yet been detected from Type Ia supernovae by current telescopes. The SKA will hopefully detect radio emission from Type Ia supernovae due to its much better sensitivity and resolution. There is a 'supernovae rate problem' for the core collapse supernovae because the optically dim ones are missed due to being intrinsically faint and/or due to dust obscuration. A number of dust-enshrouded optically hidden supernovae should be discovered via SKA1-MID/survey, especially for those located in the innermost regions of their host galaxies. Meanwhile, the detection of intrinsically dim SNe will also benefit from SKA1. The detection rate will provide unique information about the current star formation rate and the initial mass function. A supernova explosion triggers a shock wave which expels and heats the surrounding CSM and ISM, and forms a supernova remnant (SNR). It is expected that more SNRs will be discovered by the SKA. This may decrease the discrepancy between the expected and observed numbers of SNRs. Several SNRs have been confirmed to accelerate protons, the main component of cosmic rays, to very high energy by their shocks. This brings us hope of solving the Galactic cosmic ray origin's puzzle by combining the low frequency (SKA) and very high frequency (Cherenkov Telescope Array: CTA) bands' observations of SNRs.Comment: To be published in: "Advancing Astrophysics with the Square Kilometre Array", Proceedings of Science, PoS(AASKA14

Event-based photo rediscovery and resurfacing

Social networks, online photo-sharing services, messaging services, etc. include feature that provide a user with reminders of photos that may be of interest. For example, such services may resurface photos taken on the same day in the past, e.g., a year ago. Resurfacing past photos allows the user to relive memories. Viewing resurfaced photos has become a popular online activity. However, some periodic events do not occur on exactly the same day each year. For example, an annual football game may occur on different days across years (e.g., the first Monday of October, which may be a different day in the month of October), birthday celebrations which may be moved to the nearest weekend, religious holidays based on the lunar calendar, etc. This disclosure describes techniques to detect and resurface photos that depict similar periodic, e.g., annual, events that have taken place on possibly differing days. The similar annual events need not take place on the same day of the year, so long as they take place within a certain time period near the date of a particular day of interest

Regulating effect of β-ketoacyl synthase domain of fatty acid synthase on fatty acyl chain length in de novo fatty acid synthesis

Fatty acid synthase (FAS) is a multifunctional homodimeric protein, and is the key enzyme required for the anabolic conversion of dietary carbohydrates to fatty acids. FAS synthesizes long-chain fatty acids from three substrates: acetyl-CoA as a primer, malonyl-CoA as a 2 carbon donor, and NADPH for reduction. The entire reaction is composed of numerous sequential steps, each catalyzed by a specific functional domain of the enzyme. FAS comprises seven different functional domains, among which the β-ketoacyl synthase (KS) domain carries out the key condensation reaction to elongate the length of fatty acid chain. Acyl tail length controlled fatty acid synthesis in eukaryotes is a classic example of how a chain building multienzyme works. Different hypotheses have been put forward to explain how those sub-units of FAS are orchestrated to produce fatty acids with proper molecular weight. In the present study, molecular dynamics simulation based binding free energy calculation and access tunnels analysis showed that the C16 acyl tail fatty acid, the major product of FAS, fits to the active site on KS domain better than any other substrates. These simulations supported a new hypothesis about the mechanism of fatty acid production ratio: the geometric shape of active site on KS domain might play a determinate role