What's in a name and when does it matter? The hot and cold market impacts on underpricing of certification, reputation and conflicts of interest in venture capital backed Korean IPOs

This article analyses the impact of the participation of venture capital (VC) firms on underpricing in 372 businesses brought to IPO during the period 1999-2001 in KOSDAQ. Korea's second-tier stock market, KOSDAQ, has grown dramatically since 1999 and about half of the firms listed in KOSDAQ during this period were VC-backed, thus providing a good testing ground for empirical analysis. We measure VC participation in terms of pre IPO share-ownership by VC firms and attempt to differentiate IPO impacts between VCs grouped in terms of their reputation (measured by their dominance of the VC market, and by their affiliation in terms of ownership by banks and security companies). In estimating impacts we control for a wide range of variables which may affect the extent of underpricing. These include uncertainty inducing factors such as the age, size, profitability, leverage, and technical riskiness (measured by sector and R&D intensity) of the firm brought to IPO. We also control for market conditions using proxies for hot and cold market effects based on the numbers of contemporaneous IPOs, underpricing trends and market price movements. Finally in addition to allowing for the impact of underwriting quality we control for share overhang and price revision effects. We find that, controlling for other relevant factors, pre-IPO ownership by VCs has an insignificantly negative impact on underpricing in both hot and cold markets. However in cold markets reputational effects within the VC group do matter. In those conditions the top 3 VCs and those owned by or affiliated with banks are significantly associated with lower underpricing. The same is true for the quality of underwriting. However in hot market conditions none of these effects are present.Initial Public Offering; Underpricing; Venture Capital; Certification; Conflict of Interest, Informational Advantage

Detecting non-displaceable toric fibers on compact toric manifolds via tropicalizations

We provide a combinatorial way to locate non-displaceable Lagrangian toric fibers on any compact toric manifold. By taking the intersection of certain tropicalizations coming from its moment polytope, one can detect all Lagrangian toric fibers having non-vanishing Floer cohomology ([15, 16]). The intersection completely characterizes all non-displaceable toric fibers in some cases including pseudo symmetric smooth Fano varieties ([13])

I/O Schedulers for Proportionality and Stability on Flash-Based SSDs in Multi-Tenant Environments

The use of flash based Solid State Drives (SSDs) has expanded rapidly into the cloud computing environment. In cloud computing, ensuring the service level objective (SLO) of each server is the major criterion in designing a system. In particular, eliminating performance interference among virtual machines (VMs) on shared storage is a key challenge. However, studies on SSD performance to guarantee SLO in such environments are limited. In this paper, we present analysis of I/O behavior for a shared SSD as storage in terms of proportionality and stability. We show that performance SLOs of SSD based storage systems being shared by VMs or tasks are not satisfactory. We present and analyze the reasons behind the unexpected behavior through examining the components of SSDs such as channels, DRAM buffer, and Native Command Queuing (NCQ). We introduce two novel SSD-aware host level I/O schedulers on Linux, called A & x002B;CFQ and H & x002B;BFQ, based on our analysis and findings. Through experiments on Linux, we analyze I/O proportionality and stability in multi-tenant environments. In addition, through experiments using real workloads, we analyze the performance interference between workloads on a shared SSD. We then show that the proposed I/O schedulers almost eliminate the interference effect seen in CFQ and BFQ, while still providing I/O proportionality and stability for various I/O weighted scenarios

Cool White Polymer Coatings based on Glass Bubbles for Buildings.

While most selective emitter materials are inadequate or inappropriate for building applications, here we present a techno-economically viable optical coating by integrating glass bubbles within a polymer film. A controlled glass bubble volume concentration from 0 to 70% leads to a selective solar reflectivity increase from 0.06 to 0.92 while the mid-infrared emissivity remains above 0.85. Outdoor measurements show the polymer coating on a concrete surface can provide a temperature reduction up to 25 °C during the day when conduction and convection are limited and a net cooling power greater than 78 W/m2 at a cost less than $0.005/W. The impact of polymer coating on common buildings is estimated as potential annual energy savings of 2-12 MJ/m2 and CO2 emission savings of 0.3-1.5 kg/m2. More savings are expected for higher surface-area-to-volume-ratio buildings, and the polymer coating is also expected to resolve cooling issues for old buildings with no air conditioning