Robustness and Infrared Sensitivity of Various Observables in the Application of AdS/CFT to Heavy Ion Collisions

We investigate the robustness with respect to nonconformality of five properties of strongly coupled plasmas that have been calculated in N=4 supersymmetric Yang-Mills (SYM) theory at nonzero temperature, motivated by the goal of understanding phenomena in heavy ion collisions. (The properties are the jet quenching parameter, the velocity dependence of screening, and the drag and transverse and longitudinal momentum diffusion coefficients for a heavy quark pulled through the plasma.) We use a toy model in which nonconformality is introduced via a one-parameter deformation of the AdS black hole dual to the hot N=4 SYM plasma. Upon introducing a degree of nonconformality comparable to that seen in lattice calculations of QCD at temperatures a few times that of the crossover to quark-gluon plasma, we find that the jet quenching parameter is affected by the nonconformality by at most 30%, the screening length is affected by at most 20%, but the drag and diffusion coefficients for a slowly moving heavy quark can be modified by as much as 80%. However, four of the five properties that we investigate become completely insensitive to the nonconformality in the limit v -> 1. The exception is the jet quenching parameter, which is "infrared sensitive" even at v=1, where it is defined. It is the only high-velocity observable that we investigate which is sensitive to properties of the medium at infrared energy scales proportional to T, namely the scales where the quark-gluon plasma of QCD can be strongly coupled. The other four quantities all probe only scales that are larger than T by a factor that diverges as v -> 1, namely scales where the N=4 SYM plasma can be strongly coupled but the quark-gluon plasma of QCD is not.Comment: Minor revisions, including expansion of Footnote 4. Version to appear in JHEP. 36 pages, 5 figure

استثناء الاحتيال في خطابات الاعتماد - المنهجية الصينية

In 2005, the Supreme People’s Court (SPC) introduced new provisions relating to letter of credit (L/C) transactions in the People’s Republic of China (PRC). This paper will examine the effectiveness of the new provisions concerning the L/C fraud exception rules. The issue is whether the Chinese view of the fraud exception, which was introduced by the Uniform Customs and Practice Model Law for Documentary Credits (UCP), is effective and in line with accepted international views. To that end, this paper will explain the provisions and then employ a comparative approach. It will briefly compare Chinese fraud regulation with English and U.S. jurisprudence and measure effectiveness by noting the prevailing English and U.S. views. This analysis is timely because China is gaining momentum in its economic development; hence, the attitude of Chinese courts concerning the issue of trade financing with L/Cs is important. The conclusion is that, in general, Chinese regulations are in line with international jurisprudence, and therefore, the reforms are working overall. However, some gaps or questions give rise to uncertainty. This paper suggests that the gaps need to be resolved either by courts or through further regulation by the Supreme People’s Court.أدخلت المحكمة الشعبية العليا (SPC)في عام 2005 أحكامًا جديدة تتعلق بمعاملات خطابات الاعتماد (L/C) في جمهورية الصين الشعبية (PRC). ﺗﺘﻨﺎﻭﻝ ﻫﺬﻩ ﺍﻟﻮﺭﻗﺔ ﺍﻟﺒﺤﺜﻴﺔ ﻣﺪﻯ ﻓﻌﺎﻟﻴﺔ ﺍﻷﺣﻜﺎﻡ ﺍﻟﺠﺪﻳﺪﺓ ﺍﻟﻤﺘﻌﻠﻘﺔ ﺑﻘﻮﺍﻋﺪ ﺍﺳﺘﺜﻨﺎﺀ ﻣﺒﺪﺃ ﺍﻻﺣﺘﻴﺎﻝ ﻟﺨﻄﺎﺑﺎﺕ ﺍﻻﻋﺘﻤﺎﺩ. ﻭﺍﻟﻤﺴﺄﻟﺔ ﻫﻲ ﻣﺎ ﺇﺫﺍ ﻛﺎﻧﺖ ﺍﻟﻤﻨﻬﺠﻴﺔ ﺍﻟﺼﻴﻨﻴﺔ ﺍﻟﺨﺎﺻﺔ ﺑﻤﺒﺪﺃ ﺍﺳﺘﺜﻨﺎﺀ ﺍﻻﺣﺘﻴﺎﻝ، ﻭﻫﻲ ﺍﻟﻘﻮﺍﻋﺪ ﺍﻟﻤﻮﺿﻮﻋﺔ ﻓﻲ ﺇﻃﺎﺭ ﺍﻟﻘﺎﻧﻮﻥ ﺍﻟﻨﻤﻮﺫﺟﻲ ﻟﻸﻋﺮﺍﻑ ﻭﺍﻟﻤﻤﺎﺭﺳﺎﺕ ﺍﻟﻤﻮﺣﺪﺓ ﻟﻼﻋﺘﻤﺎﺩﺍﺕ ﺍﻟﻤﺴﺘﻨﺪﻳﺔ UCP، ﻓﻌّ ﺎﻟﺔ ﻭﺗﺘﻤﺎﺷﻰ ﻣﻊ ﺍﻟﻤﻨﻬﺠﻴﺎﺕ ﺍﻟﺪﻭﻟﻴﺔ ﺍﻟﻤﻘﺒﻮﻟﺔ ﻭﺍﻟﻤﻌﺘﺮﻑ ﺑﻬﺎ. ﻭﺗﺤﻘﻴﻘً ﺎ ﻟﻬﺬﻩ ﺍﻟﻐﺎﻳﺔ، ﺗﺴﺘﻌﺮﺽ ﻫﺬﻩ ﺍﻟﻮﺭﻗﺔ ﺍﻟﺒﺤﺜﻴﺔ ﺍﻷﺣﻜﺎﻡ،ﺛﻢ ﺗﺴﺘﺨﺪﻡ ﻧﻬﺠً ﺎ ﻣﻘﺎﺭﻧًﺎ. ﻭﺳﻮﻑ ﺗﺴﺘﻌﺮﺽ ﻫﺬﻩ ﺍﻟﻮﺭﻗﺔ ﺍﻟﺒﺤﺜﻴﺔ ﻟﻮﺍﺋﺢ ﻣﻜﺎﻓﺤﺔ ﺍﻻﺣﺘﻴﺎﻝ ﺍﻟﺼﻴﻨﻴﺔ ﺑﺈﻳﺠﺎﺯ ﻣﻘﺎﺭﻧﺔ ﻣﻊ ﺍﻷﺣﻜﺎﻡ ﺍﻟﻘﻀﺎﺋﻴﺔ ﻟﻠﻮﻻﻳﺎﺕ ﺍﻟﻤﺘﺤﺪﺓ، ﻭﻗﻴﺎﺱ ﻣﺪﻯ ﺍﻟﻔﻌّ ﺎﻟﻴﺔ ﻣﻦ ﺧﻼﻝ ﺍﺳﺘﻌﺮﺍﺽ ﻭﺟﻬﺎﺕ ﺍﻟﻨﻈﺮ ﺍﻟﺴﺎﺋﺪﺓ ﻓﻲ ﺍﻟﻤﻤﻠﻜﺔ ﺍﻟﻤﺘﺤﺪﺓ ﻭﺍﻟﻮﻻﻳﺎﺕ ﺍﻟﻤﺘﺤﺪﺓ ﺍﻷﻣﺮﻳﻜﻴﺔ. ﻭﻟﻘﺪ ﺟﺎﺀ ﻫﺬﺍ ﺍﻟﺘﺤﻠﻴﻞ ﻓﻲ ﺍﻟﻮﻗﺖ ﺍﻟﻤﻨﺎﺳﺐ ﺣﻴﺚ ﺇﻥ ﺍﻟﺼﻴﻦ ﺗﻜﺘﺴﺐ ﺯﺧﻤً ﺎ ﻓﻲ ﻣﺠﺎﻝ ﺍﻟﺘﻨﻤﻴﺔ ﺍﻻﻗﺘﺼﺎﺩﻳﺔ؛ ﻭﺑﺎﻟﺘﺎﻟﻲ،ﻓﺈﻥ ﻣﻮﻗﻒ ﺍﻟﻤﺤﺎﻛﻢ ﺍﻟﺼﻴﻨﻴﺔ ﻓﻴﻤﺎ ﻳﺘﻌﻠﻖ ﺑﻤﺴﺄﻟﺔ ﺍﻟﺘﻤﻮﻳﻞ ﺍﻟﺘﺠﺎﺭﻱ ﺑﺎﺳﺘﺨﺪﺍﻡ ﺧﻄﺎﺑﺎﺕ ﺍﻻﻋﺘﻤﺎﺩ ﺃﻣﺮٌ ﺑﺎﻟﻎ ﺍﻷﻫﻤﻴﺔ. ﻭﺍﻟﺨﻼﺻﺔ ﺃﻥ ﺍﻟﻠﻮﺍﺋﺢ ﺍﻟﺼﻴﻨﻴﺔ ﺑﻮﺟﻪ ﻋﺎﻡ ﺗﺘﻤﺎﺷﻰ ﻣﻊ ﺍﻟﻔﻘﻪ ﺍﻟﻘﻀﺎﺋﻲ ﺍﻟﺪﻭﻟﻲ، ﻭﺑﺎﻟﺘﺎﻟﻲ، ﻓﺈﻥ ﺍﻹﺻﻼﺣﺎﺕ ﺳﻮﻑ ﺗﻨﻄﺒﻖ ﺑﺸﻜﻞ ﺷﺎﻣﻞ ﻋﻠﻰ ﺟﻤﻴﻊ ﺍﻷﻧﻈﻤﺔ. ﺑﻴﺪ ﺃﻥ ﺑﻌﺾ ﺍﻟﺜﻐﺮﺍﺕ ﺃﻭ ﺍﻟﺘﺴﺎﺅﻻﺕ ﺗﺜﻴﺮ ﺍﻟﺸﻜﻮﻙ. ﻭﺗﺸﻴﺮ ﻫﺬﻩ ﺍﻟﻮﺭﻗﺔ ﺇﻟﻰ ﺃﻥ ﻫﺬﻩ ﺍﻟﺜﻐﺮﺍﺕ ﺗﺤﺘﺎﺝ ﺇﻟﻰ ﺣﻞ ﺇﻣﺎ ﻣﻦ ﺧﻼﻝ ﺍﻟﻤﺤﺎﻛﻢ ﺃﻭ ﻣﻦ ﺧﻼﻝ ﺍﻟﻤﺰﻳﺪ ﻣﻦ ﺍﻟﻠﻮﺍﺋﺢ ﺍﻟﺘﻲ ﺗﻀﻌﻬﺎ ﺍﻟﻤﺤﻜﻤﺔ ﺍﻟﺸﻌﺒﻴﺔ ﺍﻟﻌﻠﻴﺎ

The fraud exception in letters of credit – the Chinese approach

أدخلت المحكمة الشعبية العليا (SPC)في عام 2005 أحكامًا جديدة تتعلق بمعاملات خطابات الاعتماد (L/C) في جمهورية الصين الشعبية (PRC). ﺗﺘﻨﺎﻭﻝ ﻫﺬﻩ ﺍﻟﻮﺭﻗﺔ ﺍﻟﺒﺤﺜﻴﺔ ﻣﺪﻯ ﻓﻌﺎﻟﻴﺔ ﺍﻷﺣﻜﺎﻡ ﺍﻟﺠﺪﻳﺪﺓ ﺍﻟﻤﺘﻌﻠﻘﺔ ﺑﻘﻮﺍﻋﺪ ﺍﺳﺘﺜﻨﺎﺀ ﻣﺒﺪﺃ ﺍﻻﺣﺘﻴﺎﻝ ﻟﺨﻄﺎﺑﺎﺕ ﺍﻻﻋﺘﻤﺎﺩ. ﻭﺍﻟﻤﺴﺄﻟﺔ ﻫﻲ ﻣﺎ ﺇﺫﺍ ﻛﺎﻧﺖ ﺍﻟﻤﻨﻬﺠﻴﺔ ﺍﻟﺼﻴﻨﻴﺔ ﺍﻟﺨﺎﺻﺔ ﺑﻤﺒﺪﺃ ﺍﺳﺘﺜﻨﺎﺀ ﺍﻻﺣﺘﻴﺎﻝ، ﻭﻫﻲ ﺍﻟﻘﻮﺍﻋﺪ ﺍﻟﻤﻮﺿﻮﻋﺔ ﻓﻲ ﺇﻃﺎﺭ ﺍﻟﻘﺎﻧﻮﻥ ﺍﻟﻨﻤﻮﺫﺟﻲ ﻟﻸﻋﺮﺍﻑ ﻭﺍﻟﻤﻤﺎﺭﺳﺎﺕ ﺍﻟﻤﻮﺣﺪﺓ ﻟﻼﻋﺘﻤﺎﺩﺍﺕ ﺍﻟﻤﺴﺘﻨﺪﻳﺔ UCP، ﻓﻌّ ﺎﻟﺔ ﻭﺗﺘﻤﺎﺷﻰ ﻣﻊ ﺍﻟﻤﻨﻬﺠﻴﺎﺕ ﺍﻟﺪﻭﻟﻴﺔ ﺍﻟﻤﻘﺒﻮﻟﺔ ﻭﺍﻟﻤﻌﺘﺮﻑ ﺑﻬﺎ. ﻭﺗﺤﻘﻴﻘً ﺎ ﻟﻬﺬﻩ ﺍﻟﻐﺎﻳﺔ، ﺗﺴﺘﻌﺮﺽ ﻫﺬﻩ ﺍﻟﻮﺭﻗﺔ ﺍﻟﺒﺤﺜﻴﺔ ﺍﻷﺣﻜﺎﻡ،ﺛﻢ ﺗﺴﺘﺨﺪﻡ ﻧﻬﺠً ﺎ ﻣﻘﺎﺭﻧًﺎ. ﻭﺳﻮﻑ ﺗﺴﺘﻌﺮﺽ ﻫﺬﻩ ﺍﻟﻮﺭﻗﺔ ﺍﻟﺒﺤﺜﻴﺔ ﻟﻮﺍﺋﺢ ﻣﻜﺎﻓﺤﺔ ﺍﻻﺣﺘﻴﺎﻝ ﺍﻟﺼﻴﻨﻴﺔ ﺑﺈﻳﺠﺎﺯ ﻣﻘﺎﺭﻧﺔ ﻣﻊ ﺍﻷﺣﻜﺎﻡ ﺍﻟﻘﻀﺎﺋﻴﺔ ﻟﻠﻮﻻﻳﺎﺕ ﺍﻟﻤﺘﺤﺪﺓ، ﻭﻗﻴﺎﺱ ﻣﺪﻯ ﺍﻟﻔﻌّ ﺎﻟﻴﺔ ﻣﻦ ﺧﻼﻝ ﺍﺳﺘﻌﺮﺍﺽ ﻭﺟﻬﺎﺕ ﺍﻟﻨﻈﺮ ﺍﻟﺴﺎﺋﺪﺓ ﻓﻲ ﺍﻟﻤﻤﻠﻜﺔ ﺍﻟﻤﺘﺤﺪﺓ ﻭﺍﻟﻮﻻﻳﺎﺕ ﺍﻟﻤﺘﺤﺪﺓ ﺍﻷﻣﺮﻳﻜﻴﺔ. ﻭﻟﻘﺪ ﺟﺎﺀ ﻫﺬﺍ ﺍﻟﺘﺤﻠﻴﻞ ﻓﻲ ﺍﻟﻮﻗﺖ ﺍﻟﻤﻨﺎﺳﺐ ﺣﻴﺚ ﺇﻥ ﺍﻟﺼﻴﻦ ﺗﻜﺘﺴﺐ ﺯﺧﻤً ﺎ ﻓﻲ ﻣﺠﺎﻝ ﺍﻟﺘﻨﻤﻴﺔ ﺍﻻﻗﺘﺼﺎﺩﻳﺔ؛ ﻭﺑﺎﻟﺘﺎﻟﻲ،ﻓﺈﻥ ﻣﻮﻗﻒ ﺍﻟﻤﺤﺎﻛﻢ ﺍﻟﺼﻴﻨﻴﺔ ﻓﻴﻤﺎ ﻳﺘﻌﻠﻖ ﺑﻤﺴﺄﻟﺔ ﺍﻟﺘﻤﻮﻳﻞ ﺍﻟﺘﺠﺎﺭﻱ ﺑﺎﺳﺘﺨﺪﺍﻡ ﺧﻄﺎﺑﺎﺕ ﺍﻻﻋﺘﻤﺎﺩ ﺃﻣﺮٌ ﺑﺎﻟﻎ ﺍﻷﻫﻤﻴﺔ. ﻭﺍﻟﺨﻼﺻﺔ ﺃﻥ ﺍﻟﻠﻮﺍﺋﺢ ﺍﻟﺼﻴﻨﻴﺔ ﺑﻮﺟﻪ ﻋﺎﻡ ﺗﺘﻤﺎﺷﻰ ﻣﻊ ﺍﻟﻔﻘﻪ ﺍﻟﻘﻀﺎﺋﻲ ﺍﻟﺪﻭﻟﻲ، ﻭﺑﺎﻟﺘﺎﻟﻲ، ﻓﺈﻥ ﺍﻹﺻﻼﺣﺎﺕ ﺳﻮﻑ ﺗﻨﻄﺒﻖ ﺑﺸﻜﻞ ﺷﺎﻣﻞ ﻋﻠﻰ ﺟﻤﻴﻊ ﺍﻷﻧﻈﻤﺔ. ﺑﻴﺪ ﺃﻥ ﺑﻌﺾ ﺍﻟﺜﻐﺮﺍﺕ ﺃﻭ ﺍﻟﺘﺴﺎﺅﻻﺕ ﺗﺜﻴﺮ ﺍﻟﺸﻜﻮﻙ. ﻭﺗﺸﻴﺮ ﻫﺬﻩ ﺍﻟﻮﺭﻗﺔ ﺇﻟﻰ ﺃﻥ ﻫﺬﻩ ﺍﻟﺜﻐﺮﺍﺕ ﺗﺤﺘﺎﺝ ﺇﻟﻰ ﺣﻞ ﺇﻣﺎ ﻣﻦ ﺧﻼﻝ ﺍﻟﻤﺤﺎﻛﻢ ﺃﻭ ﻣﻦ ﺧﻼﻝ ﺍﻟﻤﺰﻳﺪ ﻣﻦ ﺍﻟﻠﻮﺍﺋﺢ ﺍﻟﺘﻲ ﺗﻀﻌﻬﺎ ﺍﻟﻤﺤﻜﻤﺔ ﺍﻟﺸﻌﺒﻴﺔ ﺍﻟﻌﻠﻴﺎ.In 2005, the Supreme People’s Court (SPC) introduced new provisions relating to letter of credit (L/C) transactions in the People’s Republic of China (PRC). This paper will examine the effectiveness of the new provisions concerning the L/C fraud exception rules. The issue is whether the Chinese view of the fraud exception, which was introduced by the Uniform Customs and Practice Model Law for Documentary Credits (UCP), is effective and in line with accepted international views. To that end, this paper will explain the provisions and then employ a comparative approach. It will briefly compare Chinese fraud regulation with English and U.S. jurisprudence and measure effectiveness by noting the prevailing English and U.S. views. This analysis is timely because China is gaining momentum in its economic development; hence, the attitude of Chinese courts concerning the issue of trade financing with L/Cs is important. The conclusion is that, in general, Chinese regulations are in line with international jurisprudence, and therefore, the reforms are working overall. However, some gaps or questions give rise to uncertainty. This paper suggests that the gaps need to be resolved either by courts or through further regulation by the Supreme People’s Court

Clickstream Big Data and “Delivery before Order Making” Mode for Online Retailers

Our research is inspired by a leading online retailer using clickstream big data to estimate customer demand and then ship items to customers or hubs near customers by a mode of “delivery before order making” (DBOM) mode. Using clickstream data to obtain advance demand information in order quantities, we integrate the forecasting with a singleitem uncapacitated dynamic lot sizing problem in a rolling-horizon environment. Using the simulated clickstream data, we evaluate the performance of DBOM mode

The Multi-Location Transshipment Problem with Positive Replenishment Lead Times

Transshipments, monitored movements of material at the same echelon of a supply chain, represent an effective pooling mechanism. With a single exception, research on transshipments overlooks replenishment lead times. The only approach for two-location inventory systems with non-negligible lead times could not be generalized to a multi-location setting, and the proposed heuristic method cannot guarantee to provide optimal solutions. This paper uses simulation optimization by combining an LP/network flow formulation with infinitesimal perturbation analysis to examine the multi-location transshipment problem with positive replenishment lead times, and demonstrates the computation of the optimal base stock quantities through sample path optimization. From a methodological perspective, this paper deploys an elegant duality-based gradient computation method to improve computational efficiency. In test problems, our algorithm was also able to achieve better objective values than an existing algorithm

UniASM: Binary Code Similarity Detection without Fine-tuning

Binary code similarity detection (BCSD) is widely used in various binary analysis tasks such as vulnerability search, malware detection, clone detection, and patch analysis. Recent studies have shown that the learning-based binary code embedding models perform better than the traditional feature-based approaches. In this paper, we proposed a novel transformer-based binary code embedding model, named UniASM, to learn representations of the binary functions. We designed two new training tasks to make the spatial distribution of the generated vectors more uniform, which can be used directly in BCSD without any fine-tuning. In addition, we proposed a new tokenization approach for binary functions, increasing the token's semantic information while mitigating the out-of-vocabulary (OOV) problem. The experimental results show that UniASM outperforms state-of-the-art (SOTA) approaches on the evaluation dataset. We achieved the average scores of recall@1 on cross-compilers, cross-optimization-levels and cross-obfuscations are 0.72, 0.63, and 0.77, which is higher than existing SOTA baselines. In a real-world task of known vulnerability searching, UniASM outperforms all the current baselines.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

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Robustness and infrared sensitivity of various observables in the application of AdS/CFT to heavy ion physics

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.Includes bibliographical references (p. 69-73).We investigate the robustness with respect to the introduction of nonconformality of five properties of strongly coupled plasmas that have been calculated in K = 4 supersymmetric Yang-Mills (SYM) theory at nonzero temperature, motivated by the goal of understanding phenomena in relativistic heavy ion collisions. (The five properties are the jet quenching parameter, the velocity dependence of screening, and the drag and transverse and longitudinal momentum diffusion coefficients for a heavy quark pulled through the plasma.) We do so using a toy model in which nonconformality is introduced via a one-parameter deformation of the AdS black hole dual to the hot KN = 4 SYM plasma. For values of this parameter which correspond to a degree of nonconformality comparable to that seen in lattice calculations of QCD thermodynamics at temperatures a few times that of the crossover to quark-gluon plasma, we find that the jet quenching parameter is affected by the nonconformality at the 30% level or less, the screening length is affected at the 20% level or less, but the drag and diffusion coefficients for a slowly moving heavy quark can be modified by as much as 80%. However, we show that all but one of the five properties that we investigate become completely insensitive to the nonconformality in the high velocity limit v --, 1. The exception is the jet quenching parameter, which is unique among the quantities that we investigate in being "infrared sensitive" even at v = 1, where it is defined. That is, it is the only high-velocity observable that we investigate which is sensitive to properties of the medium at infrared energy scales proportional to T, namely the scales where the quark-gluon plasma of QCD can be strongly coupled. The other four quantities all probe only scales that are larger than T by a factor that diverges as v -- 1, namely scales where the KN = 4 SYM plasma can be strongly coupled but the quark-gluon plasma of QCD is not.by Yeming Shi.S.B