Speculative Staging for Interpreter Optimization

Interpreters have a bad reputation for having lower performance than just-in-time compilers. We present a new way of building high performance interpreters that is particularly effective for executing dynamically typed programming languages. The key idea is to combine speculative staging of optimized interpreter instructions with a novel technique of incrementally and iteratively concerting them at run-time. This paper introduces the concepts behind deriving optimized instructions from existing interpreter instructions---incrementally peeling off layers of complexity. When compiling the interpreter, these optimized derivatives will be compiled along with the original interpreter instructions. Therefore, our technique is portable by construction since it leverages the existing compiler's backend. At run-time we use instruction substitution from the interpreter's original and expensive instructions to optimized instruction derivatives to speed up execution. Our technique unites high performance with the simplicity and portability of interpreters---we report that our optimization makes the CPython interpreter up to more than four times faster, where our interpreter closes the gap between and sometimes even outperforms PyPy's just-in-time compiler.Comment: 16 pages, 4 figures, 3 tables. Uses CPython 3.2.3 and PyPy 1.

The use of ground penetrating radar to map soil physical properties that control water flow pathways in alluvial soils : a thesis presented in partial fulfilment of the requirement for the degree of Master of Science in Agriculture at Massey University, Manawatu, New Zealand

Soil drainage models are vital for informing smart agricultural practices. Predicting soil drainage and zones where denitrification occurs, requires knowledge of the spatially varying subsurface features, for example soil-thickness, flow pathways, and depth to water table. Obtaining information about these features rapidly and non-invasively requires the use of geophysical techniques such as ground penetrating radar (GPR). While applications of GPR are diverse, ranging from geotechnical to archaeological investigations, to mineral and groundwater exploration, GPR has not been extensively applied in soil mapping for agricultural purposes across alluvial soils. The potential use of GPR for identifying subsurface features, such as the depth to gravel and water table which both influence soil drainage and denitrification processes, could benefit future developments in precision agriculture. To assess applicability of GPR for this purpose, this thesis presents research conducted on the alluvial soils at Dairy 1 farm, Massey University, Palmerston North. Radargrams were collected on two 0.4 ha plots, one arable and one pasture, using 200 MHz and 100 MHz antennas, in a 2-m grid pattern. Radargrams were ground-truthed with 13 soil cores and 21 auger holes, targeting different layers detected by GPR. The soil cores were analysed for bulk density, soil moisture and particle size. Using the 200 MHz antennas, soil textural banding was identified with specific reflection configurations within individual radargrams. These were represented when a contrasting textural boundary appeared as a continuous line of two to three bands. However, finer layering features were not identified. The 100 MHz antennas were able to detect depth to water table in the pasture plot. Soil moisture conditions were identified by a change in radar wave velocity. This appeared on radargrams as a difference in depth and radargram configuration shape. The use of Slice View images compiled from radargram data, assisted with identifying potential flow pathways and the depth to the water table across the pasture plot. Validation of radargrams with soil core samples indicates that GPR can obtain meaningful results from alluvial sediments ranging from sandy loams to silt loams. The use of GPR for delineating subsurface features in alluvial soils is a promising tool that could assist with precision agricultural practices

Peculiarities to choose sales policy tools at the Ukrainian innovatively active machine building enterprises at the economic cycle stage

The article deals with identification of the most active sales policy tools set at the innovatively active machine building enterprise, considering economic development cycles. One establishes cyclical constituent of the real GDP change time series, interconnection between real GDP lag change in one year and innovative production selling profitability from machine building enterprises. Authors determine sales policy tools impact on enterprise ability to recover from crisis and their impact lags. Methodic recommendations concerning sales policy efficient strategies choice at the machine building enterprises-innovators are investigated

サーバサイド向けJavaScript処理系におけるJust In Timeコンパイラの実装

JavaScriptは、一般的にWebアプリケーションのクライアント側の開発で用いられるが、サーバ側でもJavaScriptを用いる事かできれば、学習コストなどのアプリケーション開発コストの削減が期待できる。Webアプリケーションにおいて、処理にかかる時間の多くはI/Oにかかる時間であるが、依然として統計処理などといった時間のかかる計算を行う場合もあり、高速に実行する需要がある。しかし、JavaScriptは変数の型に多相性が存在し、実行時に型が定るまで処理が決定しないため、高速化のための静的な最適化は不向きである。そのため、頻繁に実行されるコードを実行時情報を用いてマシンコードにコンパイルし、繰り返し実行することで高速化を図る動的な最適化手法であるJust In Time (JIT) コンパイル機構が有効である。本論文は、サーバサイド向けのJavaScript仮想機械処理系において、C言語等のバックエンドとして用いられている、コンパイル基盤であるLLVMを用いたJITコンパイル機構を実装し評価した。長期間のプログラムの運用を考慮した際、コンパイルにかかる時間は非常に短い時間の割合と考えられるため、本JITコンパイル機構では高速なマシンコード生成に注力した。実行時型情報、及び型推論機構から得た情報を元に、コンパイルにおいて様々な高速化を積極的に適応した。プログラムを特定の型環境下に特殊化し、更に、オブジェクトのプロパティの取得の最適化など、幾つかのJavaScript依存の最適化や、更にLLVMの提供する様々な最適化を適応した。その結果、数値計算が中心のプログラムについて、長期間のプログラムの運用を前提とした場合、高速なマシンコードを生成が実行時間の短縮に繋がり、本機構の有効性が確認できた。電気通信大学201

"The Role of the Merchant Coalition in Pre-modern Japanese Economic Development: An Historical Institutional Analysis"

This paper examines the economic role of the merchant coalition (kabu nakama) in Japan during the the eighteenth and the first half of the nineteenth century in Japan. During this period public sector enforcement of contracts was imperfect. Kabu nakama substituted for the public sector, using a multilateral punishment strategy. When the government (Bakufu) prohibited kabu nakama in 1841, the growth rate of the real money supply contracted, efficiency of price arbitrage declined, and the inflation rate increased.

"The Role of the Merchant Coalition in Premodern Japanese Economic Development: An Historical Institutional Analysis"

This paper analyzes the role of the merchant coalition (kabu nakama) in Japan in the eighteenth and the first half of the nineteenth century, from the standpoint of Historical Institutional Analysis (Greif[1997]). The quantitative economic history literature has made clear that sustainable economic growth based on a market economy started in Japan at the end of the eighteenth century. On the other hand, from time to time the central government (Bakufu) legislated ordinances prescribing that suits on pecuniary matters would not be accepted (Aitai Sumeshi Rei). The implication is that the public system for third-party contract enforcement was not working well. The activities of merchant coalitions substituted for public third-party enforcement in premodern Japan. Many of the merchant coalitions' codes prescribed that all of each coalition's members should suspend transaction with those who cheated any one of the members of the coalition. This was the multiple punishment strategy (MPS), as formulated by Greif[1993]. The MPS of the merchant coalition reduced incentives for the players in the market to cheat, which in turn promoted development of a market economy. It is remarkable that the Japanese merchant coalition applied the MPS not only to ordinary commodity trade, but also to the putting-out system and employment. We empirically tested the above hypothesis about the function of the coalition. In 1841, the Bakufu prohibited the coalition, intending to eliminate any monopoly. This event can be regarded as a natural experiment, suitable for an investigation into the role of the coalition. The above hypothesis implies that prohibition of the coalition lowered the performance of the market economy. This implication was examined using data on the money supply and commodity prices. As predicted by the hypothesis, we found that the growth rate of the real money supply contracted and that the efficiency of price arbitrage declined.

"The Role of the Merchant Coalition in Pre-modern Japanese Economic Development: An Historical Institutional Analysis"

This paper examines the role of the merchant coalition (kabu nakama) in the eighteenth and the first half of the nineteenth century in Japan, from the standpoint of Historical Institutional Analysis (Greif[1997, 1998]). Quantitative economic history literature has made clear that market-based economic growth started around the end of the eighteenth century in Japan. On the other hand, the Bakufu, the central government, repeatedly promulgated Aitai Sumeshi Rei (Mutual Settlement Decree), prescribing that the public authorities would not accept suits on pecuniary affairs. This implies that the public system for third-party enforcement was not working well. Activities of the merchant coalition substituted for the public third-party enforcement. Many of the merchant coalitions' codes wrote that all of each coalition's members should suspend transaction with those who cheated any one of the members of the coalition. This was the multilateral punishment strategy (MPS), formulated by Greif[1993]. It is hypothesized that kabu nakama played the role of contract enforcement using the MPS, which reduced incentives for the transaction counterparts to cheat, and thereby promoted a market economy. Also, this paper empirically examines this hypothesis, using an opportunity of a natural experiment. In 1841, the Bakufu prohibited the coalition, intending to eliminate monopoly. The above hypothesis implies that prohibition of the coalition lowered the performance of the market economy. As predicted, we found that the growth rate of the real money supply contracted, that the efficiency of price arbitrage declined, and that inflation rate went up.