@inproceedings{64798,
  abstract     = {{Lead-containing piezoelectric ceramics are still the base for today’s ultrasonic transducers used in broad applications. This is partly due to missing powerful lead-free piezoelectric ceramic parts in the commercial market. There has been much research on lead-free materials but developing them into marketable parts seems to be an ongoing process. The actual exemption of ROHS has expired, but as the new exemption has already been requested, ceramic suppliers keep on selling lead containing products. Nevertheless, these should be replaced by lead-free alternatives for environmental and health issues. 
This contribution focuses on exploring the technological readiness level of lead-free hard piezoceramics for prestressed ultrasonic transducers. A small series of bolted Langevin transducers was set up with standard PZT material and three commercial lead-free variants. Results of the building process from individual ring ceramic characteristics to transducer load tests are presented. The main finding of this study is that the lead-free materials technically can compete with the standard PZT for medium-power applications. Some adaptations in the ultrasonic system must be done: the geometry must be altered to fit resonance frequency, and higher voltages or thinner ceramics are needed to achieve the same vibration level at low load. For reaching same power, the volume of lead-free ceramics must be 1.5 to 3 times larger. As already promoted in literature, mechanical losses at high vibration levels are smaller for the lead-free materials. This might help to argument lead-free piezoelectric materials in some applications.

References
1.	Directive 2011/65/EU of the European Parliament and of the Council of 8 June 2011 on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment. EUR-Lex Document 02011L0065-20240801. Available online: http://data.europa.eu/eli/dir/2011/65/2024-08-01 (accessed on 24 January 2025).
2.	Langevin, P. (1918) Method and Apparatus for Transmitting and Receiving Submarine Elastic Waves Using the Piezoelectric Properties of Quartz. French Patent Office; Patent No. FR505703.
3.	Hemsel, T.; Twiefel, J. (2023) Piezoelectric Ultrasonic Power Transducers. In Encyclopedia of Materials: Electronics; Academic Press: Oxford, UK; pp. 276–285. https://doi.org/10.1016/b978-0-12-819728-8.00047-4.
4.	ATHENA Technologie Beratung GmbH (2025) Description of Ultrasound Generator. Available online: http://shop.myathena.de/epages/12074748.sf/de_DE/?ObjectPath=/Shops/12074748/Products/AM200 (accessed on 13 January 2025).
5.	Littmann, W.; Hemsel, T.; Kauczor, C.; Wallaschek, J.; Sinha, W. (2003) Load-adaptive phase-controller for resonant driven piezoelectric devices. Proc. World Congr. Ultrason. 2003, 48, 547–550.
6.	Scheidemann, C., Bornmann, P., Littmann, W., & Hemsel, T. (2025). Lead-Free Ceramics in Prestressed Ultrasonic Transducers. Actuators, 14(2), 55. https://doi.org/10.3390/act14020055
}},
  author       = {{Scheidemann, Claus and Bornmann, Peter and Littmann, Walter and Hemsel, Tobias}},
  keywords     = {{lead free piezoelectric ceramics, bolted Langevin transducer, medium power ultrasound.}},
  location     = {{Vilnius, Lithuania}},
  title        = {{{Bolted Langevin transducers with leadfree piezoelectric ceramics}}},
  year         = {{2025}},
}

@article{62643,
  author       = {{Schwabe, Tobias and Kress, Christian and Kruse, Stephan and Weizel, Maxim and Rhee, Hanjo and Scheytt, J. Christoph}},
  journal      = {{Journal of Lightwave Technology}},
  keywords     = {{Integrated circuit modeling, Capacitance, Silicon, Modulation, Adaptation models, Semiconductor device modeling, Bandwidth, Data communication, electrooptical transmitter, equalization, free-carrier-plasma dispersion effect, modelling, optical modulator, phase shifter, silicon photonics}},
  number       = {{1}},
  pages        = {{255--270}},
  title        = {{{Forward-Biased Silicon Phase Shifter Modeling for Electronic-Photonic Co-Simulation and Validation in a 250 nm EPIC BiCMOS Technology}}},
  doi          = {{10.1109/JLT.2024.3450949}},
  volume       = {{43}},
  year         = {{2025}},
}

@article{62644,
  author       = {{Schwabe, Tobias and Kress, Christian and Sadiye, Babak and Kruse, Stephan and Scheytt, J. Christoph}},
  journal      = {{IEEE Access}},
  keywords     = {{Optical attenuators, Equalizers, Phase shifters, Optical modulation, Electro-optic modulators, Optical amplifiers, Circuits, Silicon photonics, Optical saturation, Integrated circuit modeling, Data communication, equalization, electro-optical transmitter, silicon photonics, phase shifter, optical modulator, free-carrier plasma dispersion effect, driver architectures, biasing schemes}},
  pages        = {{192433--192450}},
  title        = {{{Analysis and Design of Forward Biased Silicon Photonics Phase Shifter Equalizer Circuits}}},
  doi          = {{10.1109/ACCESS.2025.3629385}},
  volume       = {{13}},
  year         = {{2025}},
}

@techreport{49873,
  abstract     = {{This study analyzes the impact of tax complexity on the location of tax employees and tax risk. Using a hand-collected dataset of more than 7,500 tax employees from 348 European-listed multinationals, we identify two types of firm-level costs associated with tax complexity—tax employees, and tax risk. We find that firms locate more tax employees in countries with greater tax complexity. This association is particularly pronounced for complexity in tax procedures. We also find that multinationals operating in countries with high tax complexity are associated with higher tax risk. The incremental tax risk vanishes for firms that locate more tax employees in countries with highly complex tax procedures, while we find no risk reduction from additional tax employees in countries with complex tax rules. Our results reveal that multinationals eliminate 25 percent of overall tax complexity-related tax risk through targeted location of tax employees.}},
  author       = {{Giese, Henning and Koch, Reinald and Sureth-Sloane, Caren}},
  keywords     = {{tax complexity, tax complexity cost, tax department, tax employees, tax risk}},
  title        = {{{Where to Locate Tax Employees? The Role of Tax Complexity and Tax Risk Implications}}},
  doi          = {{10.2139/ssrn.4888151}},
  year         = {{2024}},
}

@article{30917,
  abstract     = {{We study lobby group formation in a two-stage model where the players rst form lobby
groups that then engage in a rent-seeking contest to inuence the legislator. However, the
outcome of the contest aects all players according to the ideological distance between the
implemented policy and the players' preferences. The players can either lobby by themselves,
form a coalition of lobbyists or free ride. We nd that free coalition formation is reasonable
if either players with moderate preferences face lobby groups with extreme preferences, or if
there are two opposing coalitions with an equal number of members. Otherwise, there are
always free riders among the players.}},
  author       = {{Block, Lukas}},
  journal      = {{Quick And Easy Journal Title}},
  keywords     = {{Group formation, Rent-seeking, Free riding}},
  title        = {{{Coalition formation versus free riding in rent-seeking contests}}},
  year         = {{2022}},
}

@inproceedings{29803,
  abstract     = {{Ultrasonic wire bonding is a solid-state joining process used to form electrical interconnections in micro and
power electronics and batteries. A high frequency oscillation causes a metallurgical bond deformation in
the contact area. Due to the numerous physical influencing factors, it is very difficult to accurately capture
this process in a model. Therefore, our goal is to determine a suitable feed-forward control strategy for the
bonding process even without detailed model knowledge. We propose the use of batch constrained Bayesian
optimization for the control design. Hence, Bayesian optimization is precisely adapted to the application of
bonding: the constraint is used to check one quality feature of the process and the use of batches leads to
more efficient experiments. Our approach is suitable to determine a feed-forward control for the bonding
process that provides very high quality bonds without using a physical model. We also show that the quality
of the Bayesian optimization based control outperforms random search as well as manual search by a user.
Using a simple prior knowledge model derived from data further improves the quality of the connection.
The Bayesian optimization approach offers the possibility to perform a sensitivity analysis of the control
parameters, which allows to evaluate the influence of each control parameter on the bond quality. In summary,
Bayesian optimization applied to the bonding process provides an excellent opportunity to develop a feedforward
control without full modeling of the underlying physical processes.}},
  author       = {{Hesse, Michael and Hunstig, Matthias and Timmermann, Julia and Trächtler, Ansgar}},
  booktitle    = {{Proceedings of the 11th International Conference on Pattern Recognition Applications and Methods (ICPRAM)}},
  isbn         = {{978-989-758-549-4}},
  keywords     = {{Bayesian optimization, Wire bonding, Feed-forward control, model-free design}},
  location     = {{Online}},
  pages        = {{383--394}},
  title        = {{{Batch Constrained Bayesian Optimization for UltrasonicWire Bonding Feed-forward Control Design}}},
  year         = {{2022}},
}

@techreport{37136,
  abstract     = {{This study examines the relation between voluntary audit and the cost of debt in private firms. We use a sample of 4,058 small private firms operating in the period 2006‐2017 that are not subject to mandatory audits. Firms decide for a voluntary audit of financial statements either because the economic setting in which they operate effectively forces them to do so (e.g., ownership complexity, export‐oriented supply chain, subsidiary status) or because firm fundamentals and/or financial reporting practices limit their access to financial debt, both reflected in earnings quality. We use these factors to model the decision for voluntary audit. In the outcome analyses, we find robust evidence that voluntary audits are associated with higher, rather than lower, interest rate by up to 3.0 percentage points. This effect is present regardless of the perceived audit quality (Big‐4 vs. non‐Big‐4), but is stronger for non‐Big‐4 audits where auditees have a stronger position relative to auditors. Audited firms’ earnings are less informative about future operating performance relative to unaudited counterparts. We conclude that voluntary audits facilitate access to financial debt for firms with higher risk that may otherwise have no access to this form of financing. The price paid is reflected in higher interest rates charged to firms with voluntary audits – firms with higher information and/or fundamental risk.}},
  author       = {{Ichev, Riste and Koren, Jernej and Kosi, Urska and Sitar Sustar, Katarina and Valentincic, Aljosa}},
  keywords     = {{private firms, voluntary audit, cost of debt, self‐selection bias, risk}},
  title        = {{{Cost of Debt for Private Firms Revisited: Voluntary Audits as a Reflection of Risk}}},
  year         = {{2021}},
}

@article{25212,
  abstract     = {{Finding a good query plan is key to the optimization of query runtime. This holds in particular for cost-based federation
engines, which make use of cardinality estimations to achieve this goal. A number of studies compare SPARQL federation engines across different performance metrics, including query runtime, result set completeness and correctness, number of sources selected and number of requests sent. Albeit informative, these metrics are generic and unable to quantify and evaluate the accuracy of the cardinality estimators of cost-based federation engines. To thoroughly evaluate cost-based federation engines, the effect of estimated cardinality errors on the overall query runtime performance must be measured. In this paper, we address this challenge by presenting novel evaluation metrics targeted at a fine-grained benchmarking of cost-based federated SPARQL query engines. We evaluate five cost-based federated SPARQL query engines using existing as well as novel evaluation metrics by using LargeRDFBench queries. Our results provide a detailed analysis of the experimental outcomes that reveal novel insights, useful for the development of future cost-based federated SPARQL query processing engines.}},
  author       = {{Qudus, Umair and Saleem, Muhammad and Ngonga Ngomo, Axel-Cyrille and Lee, Young-Koo}},
  issn         = {{2210-4968}},
  journal      = {{Semantic Web}},
  keywords     = {{SPARQL, benchmarking, cost-based, cost-free, federated, querying}},
  number       = {{6}},
  pages        = {{843--868}},
  publisher    = {{ISO Press}},
  title        = {{{An Empirical Evaluation of Cost-based Federated SPARQL Query Processing Engines}}},
  doi          = {{10.3233/SW-200420}},
  volume       = {{12}},
  year         = {{2021}},
}

@article{64018,
  abstract     = {{CO oxidation is an extensively studied reaction in heterogeneous catalysis due to its seeming simplicity and its great importance for emission control. However, the role of particle size and more specifically structure sensitivity in this reaction is still controversial. In the present study, colloidal “surfactant-free” Pt nanoparticles (NPs) in a size regime of 1–4 nm with narrow size distribution and control over particle size were synthesized and subsequently supported on Al2O3 to prepare model catalysts. CO oxidation was performed using Pt NPs catalysts with particles sizes of 1, 2, 3, and 4 nm at different reaction temperatures. It is shown that the reaction exhibits a particle size effect that depends strongly on the reaction conditions. At 170 °C, the reaction seems to proceed within the same kinetic regime for all particle sizes, but the surface normalized activity depends strongly on the particle size, with maximum activity for nanoparticles 2 nm in diameter. A temperature increase to 200 °C leads to a change of the kinetic regime that depends on the particle size. For Pt NPs 1 nm in diameter a reaction order of 1 for O2 was observed, indicating that O2 adsorbs molecularly and dissociates in a following step, which represents the generally accepted mechanism on Pt surfaces. The reaction order of −1 for CO demonstrates that the surface is saturated with CO under reaction conditions. With increasing particle size, the reaction orders of O2 and CO change. For particles 2 nm in size, an increase in temperature also results in reaction orders of 1 for O2 and −1 for CO; NPs of 3 and 4 nm, even at higher temperatures, show no clear kinetic behavior that can be explained by a single reaction mechanism. Instead, the Boudouard reaction between two adjacent adsorbed CO molecules was identified as an important additional reaction pathway that occurs preferentially on large particles and causes more complex kinetics.}},
  author       = {{Neumann, Sarah and Gutmann, Torsten and Buntkowsky, Gerd and Paul, Stephen and Thiele, Greg and Sievers, Heiko and Bäumer, Marcus and Kunz, Sebastian}},
  journal      = {{Journal of Catalysis}},
  keywords     = {{Solid state NMR, “Surfactant-free” platinum nanoparticles, CO oxidation, Particle size effect, Structure sensitivity}},
  pages        = {{662–672}},
  title        = {{{Insights into the reaction mechanism and particle size effects of CO oxidation over supported Pt nanoparticle catalysts}}},
  doi          = {{10.1016/j.jcat.2019.07.049}},
  volume       = {{377}},
  year         = {{2019}},
}

@inproceedings{59220,
  author       = {{Schwabe, Tobias and Balke, Axel and Bezuidenhout, Petrone H. and Reker, Julia and Meyers, Thorsten and Joubert, Trudi-Heleen and Hilleringmann, Ulrich}},
  booktitle    = {{Fifth Conference on Sensors, MEMS, and Electro-Optic Systems}},
  editor       = {{du Plessis, Monuko}},
  keywords     = {{sensing, zinc oxide, thin-film transistor, oxygen measurement, low-cost electronics, water quality analysis, printable electronics, flexible electronics}},
  pages        = {{1104316}},
  publisher    = {{SPIE}},
  title        = {{{Oxygen detection with zinc oxide nanoparticle structures}}},
  doi          = {{10.1117/12.2501507}},
  volume       = {{11043}},
  year         = {{2019}},
}

@article{4947,
  abstract     = {{Manufacturers increasingly integrate information and communication technologies into their products so that they can provide IT-based services. Organizations that formerly concentrated on transactional sales thus confront a new challenge associated with managing service usage—retention and extracting value from investments in smart technology. This study combines a marketing and an information systems perspective in a field study conducted jointly with a large European car manufacturer. Understanding the renewal decision for IT-based service contracts requires knowledge from both disciplines. The paper shows that combining behavioral predictor variables stemming from marketing research and technology-related perceptual variables stemming from technology acceptance research increases the explanatory power and prediction accuracy of forecasting models for customer renewal decisions. Specifically, the authors show that perceptions of usefulness become more important the longer customers use IT-based services and the more services they use within the service contract.}},
  author       = {{Wangenheim, Florian v and Wünderlich, Nancy and Schumann, Jan H}},
  journal      = {{Journal of Business Research}},
  keywords     = {{IT-based service, Smart services, Contract renewal, Retention, Customer churn, Free trial}},
  number       = {{79}},
  pages        = {{181----188}},
  publisher    = {{Elsevier}},
  title        = {{{Renew or cancel? Drivers of customer renewal decisions for IT-based service contracts}}},
  year         = {{2017}},
}

@article{4586,
  abstract     = {{This study examines the loan-pricing behavior of German banks for a large variety of retail and corporate loan products. We find that a bank’s operational efficiency is priced in bank loan rates and alters interest-setting behavior. Specifically, we establish that a higher degree of operational efficiency leads to lower loan markups, which makes prices more competitive and smoothes the setting of interest rates. By employing state-of-the-art stochastic frontier efficiency measures to capture a bank’s operational efficiency, we take a look at the bank customers’ perspective and demonstrate the extent to which bor-rowers benefit from cost-efficient banking. }},
  author       = {{Schlueter, Tobias and Busch, Ramona and Sievers, Soenke and Hartmann-Wendels, Thomas}},
  journal      = {{Credit and Capital Markets--Kredit und Kapital}},
  keywords     = {{interest rate pass-through models, error correction models, bank efficiency, cost efficiency, stochastic frontier analysis}},
  number       = {{1}},
  pages        = {{93--125}},
  title        = {{{Loan Pricing: Do Borrowers Benefit from Cost-Efficient Banking?}}},
  doi          = {{10.3790/ccm.49.1.93}},
  volume       = {{49}},
  year         = {{2016}},
}

@inproceedings{9959,
  abstract     = {{Ultrasonic heavy wire bonding is a commonly used technology to conduct electrical devices in power electronics. In order to facilitate powerful solutions combined with an increased efficiency, involving a material change from aluminum to copper wire as conductor material takes place in recent years. Due to the material related properties, copper wire bonding requires significant higher bond processing parameters such as bond force and ultrasonic power compared to aluminum which can lead to damages or a failure of the bonded component. Therefore, a profound knowledge of the processes prevailing during wire bonding is essential to optimize the application of the copper wires and consequently to achieve the demands on quality and reliability. The behavior of different natural surface oxides of aluminum and copper are assumed to be one reason for the deviation in the required bond parameters. Accordingly, the impact of differently pre-treated substrates surfaces on which the bonding is applied were investigated in this study. First, all conditions investigated (as-received, oxidefree, AlOx and the CuOx) were characterized by utilizing scanning electron microscopy, energy dispersive X-ray spectroscopy, focused ion beam microscopy and atomic force microscopy. In addition, hardness tests were performed as well as perthometer measurements. Afterwards, a 500 $\mu$ m copper wire was bonded on the generated surfaces investigated. In consideration of the roughness, shear test of various bond times and microscopic images were evaluated. Finally, the results were compared and discussed. Overall, the current study indicates that an Al-oxide layer is beneficial for welding process in Cu wire bonding. On the contrary, the Cu-oxide is detrimental and leads to a delayed welding of the joining parts. Based on the obtained results, it can be expected that due to an ideal set of Al-oxide layers, lower optimal bond parameters can used to reach high bond strength with good reliability properties.}},
  author       = {{Eacock, Florian and Unger, Andreas and Eichwald, Paul and Grydin, Olexandr and Hengsbach, Florian and Althoff, Simon and Schaper, Mirko and Guth, Karsten}},
  booktitle    = {{IEEE 66th Electronic Components and Technology Conference}},
  keywords     = {{Ultrasonic copper wire bonding, Al-oxide, Cuoxide, oxide-free, roughness, morphology}},
  pages        = {{2111--2118}},
  title        = {{{Effect of different oxide layers on the ultrasonic copper wire bond process}}},
  doi          = {{10.1109/ECTC.2016.91}},
  year         = {{2016}},
}

@article{4035,
  abstract     = {{We examine whether the mandated introduction of International Financial Reporting Standards (IFRS) is associated with the propensity to access the public rather than private debt market and the cost of debt. We use a global sample of public bonds and private loans and find that mandatory IFRS adopters are more likely, post-IFRS, to issue bonds than to borrow privately. We also find that mandatory IFRS adopters pay lower bond yield spreads, but not lower loan spreads, after the mandate. These findings are consistent with debt providers responding positively to financial reporting of higher quality and comparability, but only when there is a greater reliance on publicly available financial statements than private communication. Lastly, we document that the observed debt market benefits are concentrated in countries with larger differences between domestic GAAP and IFRS and are present even for EU countries that did not experience concurrent financial reporting enforcement or other institutional reforms. Overall, our study documents positive economic consequences around the mandated IFRS adoption for corporate debt financing and, in particular, for bond financing.}},
  author       = {{Florou, Annita and Kosi, Urska}},
  issn         = {{1573-7136}},
  journal      = {{Review of Accounting Studies}},
  keywords     = {{Accounting regulation, IFRS, Accounting quality, Public and private debt markets, Cost of debt}},
  number       = {{4}},
  pages        = {{1407--1456}},
  title        = {{{Does mandatory IFRS adoption facilitate debt financing?}}},
  doi          = {{10.1007/s11142}},
  volume       = {{20}},
  year         = {{2015}},
}

@article{9878,
  abstract     = {{(K,Na)NbO3 ceramics have attracted much attention as lead-free piezoelectric materials with high piezoelectric properties. High-quality (K,Na)NbO3 ceramics can be sintered using KNbO3 and NaNbO3 powders synthesized by a hydrothermal method. In this study, to enhance the quality factor of the ceramics, high-power ultrasonic irradiation was employed during the hydrothermal method, which led to a reduction in the particle size of the resultant powders.}},
  author       = {{Isobe, G. and Maeda, Takafumi and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}},
  issn         = {{0885-3010}},
  journal      = {{Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on}},
  keywords     = {{Q-factor, ceramics, crystal growth from solution, particle size, piezoelectric materials, potassium compounds, powders, sintering, sodium compounds, ultrasonic effects, (K0.48Na0.52)NbO3, KNbO3 powders, NaNbO3 powders, high-power ultrasonic irradiation, lead-free piezoelectric materials, lead-free piezoelectric powders, particle size reduction, piezoelectric properties, quality factor, sintered (K0.48Na0.52)NbO3 ceramics, sintering, ultrasonic-assisted hydrothermal method, Acoustics, Ceramics, Lead, Piezoelectric materials, Powders, Radiation effects, Transducers}},
  number       = {{2}},
  pages        = {{225--230}},
  title        = {{{Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics}}},
  doi          = {{10.1109/TUFFC.2014.6722608}},
  volume       = {{61}},
  year         = {{2014}},
}

@article{20863,
  abstract     = {{This article examines and extends research on the relation between the capital asset pricing model market beta, accounting risk measures and macroeconomic risk factors. We employ a beta decomposition approach that nests competing models with different business risk proxies and allows to frame cross-model comparison. Because model tests require estimated independent variables resulting in measurement error, we empirically estimate three comparable model specifications with instrumental variable estimators and for the first time provide thorough instrument diagnostics in this setting. Correcting for the heretofore neglected weak instruments problem we find that growth risk (i.e., the risk of firm sales variations that are inconsistent with the market wide trends), is the business risk that explains cross-sectional variations in market beta best.}},
  author       = {{Schlueter, Tobias and Sievers, Sönke}},
  issn         = {{0924-865X}},
  journal      = {{Review of Quantitative Finance and Accounting (VHB-JOURQUAL 3 Ranking B)}},
  keywords     = {{CAPM, Cost of capital, Accounting beta, Intrinsic business risk, Growth risk, Instrumental variables}},
  number       = {{3}},
  pages        = {{535--570}},
  title        = {{{Determinants of market beta: the impacts of firm-specific accounting figures and market conditions}}},
  doi          = {{10.1007/s11156-013-0352-1}},
  year         = {{2013}},
}

@article{5108,
  abstract     = {{This study integrates the government in the context of company valuation. Our framework allows to analyze and to quantify the risk-sharing effects and conflicts of interest between the government and the shareholders when firms follow different financial policies. We provide novel evidence that firms with fixed future levels of debt might invest more than socially desirable. Economically, this happens if the gain in tax-shields is big enough to outweigh the loss in the unlevered firm value. Our findings have implications for the practice of investment subsidy programs provided by the government to avoid fostering investments beyond the socially optimal level. }},
  author       = {{Kreutzmann, Daniel and Sievers, Sönke and Mueller, Christian}},
  journal      = {{Applied Financial Economics (VHB-JOURQUAL 3 Ranking C)}},
  keywords     = {{corporate tax claim, company valuation, optimal investment, cost of capital}},
  number       = {{11}},
  pages        = {{977--989}},
  publisher    = {{Taylor \& Francis}},
  title        = {{{Investment distortions and the value of the government's tax claim}}},
  doi          = {{10.1080/09603107.2013.786161}},
  volume       = {{23}},
  year         = {{2013}},
}

@inproceedings{37109,
  abstract     = {{This study examines the effect of audit on private firms’ cost of debt. We use a sample of 1,949 small private firms operating in the period 2006-2010 with optional financial statement audit. High quality data allows us to construct a more precise interest rate measure than existing studies employ. After controlling for obvious sources of demand for voluntary audits (ownership complexity, subsidiary status, bank relations), we find a robust central result that voluntary audits increase rather than decrease the cost of debt financing, contrary to several existing studies. This finding indicates that voluntary audits are generally treated as “adopting a label” and penalised by creditors, regardless of the perceived auditor quality as a result of the lemon problem in the audit market. Even Big-4 audits increase the cost of debt, likely as a result due to the lemon problem in the audit market, although the increase is smaller than for non-Big-4 audits. The results are sensitive to the estimation method used (OLS, Heckman’s two-step, PSM) and (sub-)sample selection. We show that disregarding the underlying assumptions of these estimation methods may lead to incorrect inferences. Additional analyses show that audited firms’ reported earnings are less informative about future operating performance than earnings of their unaudited counterparts. Our results also indicate that results are sensitive to cost of debt definition and this might have affected the results reported in the existing literature.}},
  author       = {{Kosi, Urska and Koren, Jerney and Valentincic, Aljosa}},
  keywords     = {{private firms, voluntary audit, cost of debt, self-selection bias, lemon problem}},
  location     = {{Paris, France}},
  title        = {{{Does Financial Statement Audit Reduce the Cost of Debt of Private Firms?}}},
  year         = {{2013}},
}

@inproceedings{9788,
  abstract     = {{A hydrothermal method utilizes a crystallization process in the solution so that the pure and high-quality powders can be realized. Sintering from the hydrothermal KNbO3 and NaNbO3 powders, a high-dense lead-free piezoelectric (K,Na)NbO3 ceramics could be obtained (density: 98.8\%). Concerning about the g33 constant, high value as large as commercial PZT ceramics was measured. Therefore, the hydrothermal (K,Na)NbO3 ceramics is usable for the sensors and the energy harvesting devices. To demonstrate the (K,Na)NbO3 ceramics, a hydrophone sensor was fabricated and evaluated.}},
  author       = {{Maeda, Takafumi and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}},
  booktitle    = {{Ultrasonics Symposium (IUS), 2012 IEEE International}},
  issn         = {{1948-5719}},
  keywords     = {{crystallisation, hydrophones, piezoceramics, potassium compounds, powder technology, powders, sensors, sintering, sodium compounds, (K0.48Na0.52)NbO3, KNbO3 powder, NaNbO3 powder, crystallization, energy harvesting devices, g33 constant, hydrophone sensor, hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics, hydrothermal method, piezoelectric applications, sintering, Materials, Transducers}},
  pages        = {{194--195}},
  title        = {{{Piezoelectric applications of hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics}}},
  doi          = {{10.1109/ULTSYM.2012.0048}},
  year         = {{2012}},
}

@inproceedings{36994,
  abstract     = {{This paper proposes a quality driven, simulation based approach to functional design verification, which applies mainly to IP-level HDL designs with well specified test instruction format and is evaluated on a soft microprocessor core MB-LITE [5]. The approach utilizes mutation analysis as the quality metric to steer an automated simulation data generation process. It leads to a simulation flow with two phases towards an enhanced mutation analysis result. First in a random simulation phase, an in-loop heuristics is deployed and adjusts dynamically the test probability distribution so as to improve the coverage efficiency. Next, for each remaining hard-to-kill mutant, a search heuristics on test input space is developed to iteratively locate a target test, using a specific objective cost function for the goal of killing HDL mutant. The effectiveness of this integrated two-phase simulation flow is demonstrated by the results with the MB-LITE microprocessor IP.}},
  author       = {{Xie, Tao  and Müller, Wolfgang and Letombe, Florian}},
  booktitle    = {{Proceedings of SOCC2012}},
  keywords     = {{Analytical models, Hardware design languages, Microprocessors, Cost function, Data models, Search problems, IP networks}},
  publisher    = {{IEEE}},
  title        = {{{Mutation-Analysis Driven Functional Verification of a Soft Microprocessor}}},
  doi          = {{10.1109/SOCC.2012.6398362}},
  year         = {{2012}},
}

