Model-Checking Behavioral Specification of BPEL Applications

AbstractTo provide a framework to compose lots of specialised services flexibly, BPEL is proposed to describe Web service flows. Since the Web service flow description is basically a distributed collaboration, writing correct programs in BPEL is not easy. Verifying BPEL program prior to its execution is essential. This paper proposes a method to extract the behavioral specification from a BPEL appliation program and to analyze it by using the SPIN model checker. With the adequate abstraction method and support for DPE, the method can analyze all the four example cases in the BPEL standard document

"Bank Health and Investment: An Analysis of Unlisted Companies in Japan"

To the extent that a borrower faces switching costs in a relationship with an individual bank, bank-specific financial health might affect a borrower's cost of funds. The costs would be particularly large for firms that have a close relationship with limited number of banks. The purpose of this paper is to investigate whether weakened financial conditions of banks reduced investment of small and medium firms in Japan. Estimating Tobin's Q investment functions, we examine the determinants of investment for unlisted Japanese companies in the late 1990s and the early 2000s. We find that several measures on bank-specific financial health have significantly large impacts on borrower's investment, even when observable characteristics relating to Tobin's Q, cash-flow, and leverage are controlled for. We also find that multiple banking relationships, which tend to have a negative impact on investment in general, may be beneficial in relieving a hold up problem when deteriorated bank health does matter.

"Deteriorating Bank Health and Lending in Japan: Evidence from Unlisted Companies Undergoing Financial Distress"

When a borrower faces an informational hold-up problem, deteriorating bank health might reduce a borrower's credit availability. However, a bank with an impaired balance sheet might attempt to "gamble for resurrection" and hence increase risky lending to "zombie" firms. The purpose of this paper is to investigate what impacts the weakened financial conditions of banks had on loans outstanding to medium-size firms in Japan. Estimating lending functions, we examine the determinants of lending to unlisted Japanese companies in the late 1990s and early 2000s. We find that two alternative measures of bank health -regulatory capital adequacy ratios and ratios of non-performing loans (NPLs)- had opposite impacts on lending. In the case of regulatory capital adequacy ratios, its deterioration had a perverse impact on lending. The deteriorating NPL ratios, however, increased lending to troubled firms to keep otherwise economically bankrupt firms alive.

Deteriorating Bank Health and Lending in Japan: Evidence from Unlisted Companies Undergoing Financial Distress (Subsequently published in "Journal of the Asia Pacific Economy" Vo.11, No.4, December 2006, pp.482-501. )

When a borrower faces an informational hold-up problem, deteriorating bank health might reduce a borrower's credit availability. However, a bank with an impaired balance sheet might attempt to "gamble for resurrection" and hence increase risky lending to "zombie" firms. The purpose of this paper is to investigate what impacts the weakened financial conditions of banks had on loans outstanding to medium-size firms in Japan. Estimating lending functions, we examine the determinants of lending to unlisted Japanese companies in the late 1990s and early 2000s. We find that two alternative measures of bank health -regulatory capital adequacy ratios and ratios of non-performing loans (NPLs)- had opposite impacts on lending. In the case of regulatory capital adequacy ratios, its deterioration had a perverse impact on lending. The deteriorating NPL ratios, however, increased lending to troubled firms to keep otherwise economically bankrupt firms alive.

Integrated Model Checking of Static Structure and Dynamic Behavior using Temporal Description Logics

This paper presents a new notation for the formal representation of the static structure and dynamic behavior of software, based on description logics and temporal logics. The static structure as described by UML class diagrams is represented formally by description logics while the dynamic behavior is represented by linear temporal logic and state transition systems. We integrate these descriptions of static and dynamic aspects into a single formalism called LTLDL. LTLDL enables a concise and natural yet precise definition of the behavior of software w.r.t. UML class diagrams and state transition diagrams. We demonstrate our approach on the sake warehouse problem. Further, we describe how properties of finite LTLDL models can be analyzed based on bounded model checking and SMT (satisfiability modulo theory) solving. We implemented a restricted SMT solver for finite sets and relations. This SMT solver helped to reduce the model checking runtime significantly as compared to bounded model checking with existing tools