Toward the patent thicket detection : an empirical study on Japanese ARIB patent pool

Patent pool may be the solution for dissolving the economic inefficiencies caused by the existence of the patent thicket. In order to determine whether this is the case or not, the index that clarifies the existence of the patent thicket is necessary. In this paper, using the simple index (which Clarkson (2005) proposed) focused on the citation relationship of the patent network, I examine whether there exists patent thicket over the patent space surrounding Japanese ARIB patent pool. On the country of Clarkson’s results, the density of citation in the pooled patent intra-network is thinner than that in the patent space surrounding the pool. However, through focusing on the relationship between pooled patents and their “hull”, it is verified that there exists patent thicket over the ARIB patent pool.文部科学省科学研究費（基盤研究(A)）2007年度～2009年度、研究課題番号：19203015、代表者：土井教

A sustainable public procurement system for large-scale natural disasters : the case of the temporary housing program after The East Japan Earthquake

After large-scale natural disasters, governments must procure enormous amounts of many sorts efficiently without delay by concluding the discrete contracts. In addition, these procurements should not impede recovery by individual in market economies. In this paper, by focusing Japanese temporary housing program after East Japan Earthquake, I consider the important factors necessary to achieve desired public procurement during emergency period. After explaining Japanese pre-disaster rules and post-disaster response after the earthquake, I show that the price of temporary house was influenced heavily by the introduction of ad hoc program using a statistic analysis. Based on this discussion, I point out that this ad hoc policy may cause time-inconsistency problem, and adverse impact on the prevention for hazards. In this meaning, to maintain time-consistency is very important for executing public procurement after hazards

Simple economics of backward compatibility in the presence of network effects

We analyze the effects of an incumbent’s investment in backward compatibility of new products with old ones in the presence of network effects. Under consumer’s utility function consisting of two components, “stand-alone valuation” and “network-dependent valuation”, we show that incumbent’s investment level in backward compatibility always exceeds the social optimum because it raises consumers’ switching costs in socially undesirable way. In addition to this, this divergence of incumbent’s investment from a socially optimal one strongly depends on consumer’s utility. Using a specified utility function, it is shown that this divergence could increase with the degree of complementarity between two components in utility function under some situations

Licensing and R&D Investment of Duopolistic Firms with Partially Complementary Technologies

We consider research and development (R&D) investment competition between duopolistic firms that independently invest in two complementary technologies to produce their products. By "partially complementary technologies", we mean that each firm can produce the goods without both technologies but they incur more redundant costs than with both technologies. We derive the investment competition equilibria in R&D of the two technologies with and without a licensing system. By comparing R&D investment levels in the two equilibria, we show that the licensing system discourages R&D investment in most cases; however, it encourages R&D investment in some cases when the duopolistic firms can produce the goods using both technologies. We also show that (cross-) licensing increases the expected social surplus at the symmetric equilibrium.partially complementary technologies, licensing system, duopoly, R&D investment

A Cross-Licensing System Discourages R&D Investments In Completely Complementary Technologies

We consider the research and development (R&D) investment com petition of duopolistic firms in completely complementary technologies. By "completely complementary technologies," we mean that no firm can produce the goods without both of the technologies. We derive the investments competition equilibria in R&D of the two completely complementary technologies with and without a cross-licensing system. By comparing R&D investment levels in the two equilibria, we show that the cross-licensing system discourages the R&D invest ments when the duopolistic firms produce goods by using the two completely complementary technologies.completely complementary technologies, cross-licensing system, R&D investments

Parallel Imports, Drag Price Control and Pharmaceutical Innovation

This paper examines how parallel importation influences pharmaceutical innovation and the welfare of the economy, when crossnational drug price differentials occur not only because of demand elasticity based factors, but also governmental drug price control based factors. By explicitly considering the governmental drug price control baaed factors, this paper shows that parallel importation may enhance pharmaceutical innovation, when the bargaining power of a foreign government is strong and the price elasticity of demand in the foreign market is small. We also show that the increase in R&D induced by parallel imports may even increase the consumer surplus of a country with high demand elasticities and which could face relatively low drug prices, if parallel imports were not allowed.Parallel Imports, Pharmaceutical Innovation, Drug Price Control

Japanese agriculture cooperatives in food manufacturing industries

Food manufacturing by agriculture cooperatives is portrayed as an enterprise that is owned by the suppliers of raw agricultural products. Typically, in this type of enterprise, decision making is democratically made by the member farmers, and the surplus is divided among them according to the amount of raw agricultural products they supply to the firm. In this paper, we seek to find comparative efficiency and inefficiency of food manufacturing firms run by agriculture cooperatives

Sunk costs of capital and predominance of investor-owned firms in market economies

This paper examines why investor-owned firms are predominant in market economies. It is assumed that firm owners and outside traders are asymmetrically informed of venture risks, and that are sunk costs associated with investment in physical and human capital. Then, we undertake an efficiency comparison between investor-owned and worker-owned firms. We find that it is efficient when the input supplier (the investor or worker) who incurs large sunk costs owns the firm. This is because such an input supplier can credibly signal to the other input supplier that he in fact has a safe project. An empirical study based on the Japanese manufacturing industry seems to support the theoretical result

Constraining the Age and Distance of the Galactic Supernova Remnant G156.2+5.7 by H-alpha Expansion Measurements

We present deep H-alpha images of portions of the X-ray bright but optically faint Galactic supernova remnant G156.2+5.7, revealing numerous and delicately thin nonradiative filaments which mark the location of the remnant's forward shock. These new images show that these filaments have a complex structure not visible on previous lower resolution optical images. By comparing H-alpha images taken in 2004 at the McDonald Observatory and in 2015-2016 at the Kiso Observatory, we set a stringent 1-sigma upper limit of expansion to be 0.06 arcsec/yr. This proper motion, combined with a shock speed of 500 km/s inferred from X-ray spectral analyses, gives a distance of > 1.7 kpc. In addition, a simple comparison of expansion indices of several SNRs allows us to infer the age of the remnant to be a few 10,000 yr old. These estimates are more straightforward and reliable than any other previous studies, and clearly rule out a possibility that G156.2+5.7 is physically associated with part of the Taurus-Auriga cloud and dust complex at a distance of 200-300 pc.Comment: 16 pages, 5 figures, accepted for publication in The Astrophysical Journa