The Late Paleocene–Eocene Extension and Differential Denudation in the Eastern Daqingshan Mountains Around the Northeastern Margin of the Ordos Block, Western North China Craton, Constrained by Apatite (U-Th)/He Thermochronology

The initial timing of extension during the Cenozoic around the northeastern margin of the Ordos Block, western North China Craton (NCC), is still poorly constrained. Apatite (U-Th)/He low-temperature thermochronology was thus applied on eight pre-Cenozoic granitic and gneissic samples transecting the eastern Daqingshan Mountains, northeastern margin of the Ordos Block, to investigate the denudation and cooling event related to the onset of extension therein. Four mean corrected AHe ages in the southern part are overlapped within the standard deviations of 50.0 ± 0.4 to 45.0 ± 8.0 Ma. However, three mean corrected AHe ages in the northern part are prominently older of 99.2 ± 11.0 to 86.6 ± 17.1 Ma, with the rest one of 56.1 ± 8.6 Ma. Altogether, they show a younger-older-younger-older pattern along the transect correlated with the normal faults. AHe thermal history modeling results further demonstrate extensive cooling during the Late Cretaceous but differential cooling during the Late Paleocene–Eocene. The Late Cretaceous extensive cooling in the eastern Daqingshan Mountains, as well as the contemporaneous deposition hiatus in both the eastern Daqingshan Mountains and the Hohhot Depression, together indicates overall denudation in the northeastern margin of the Ordos Block at that time. The Late Paleocene–Eocene differential cooling is probably induced by the tilting of the eastern Daqingshan Mountains as a result of the extension suggested by the distribution of AHe ages. It corresponds to the syn-tectonic subsidence in the Hohhot Depression, indicating a basin-mountain coupling. Regional comparative analysis manifests similar extension around the Ordos Block and more widely across the NCC during the Late Paleocene–Eocene. Temporally, kinematically, and dynamically coupled with this regional extension event, the subduction of the Izanagi-Pacific plate probably plays a major role. However, the contribution of the India-Asia collision could not be ignored

Understanding and Simulating Software Evolution

The important roles of software in modern life have prompted people to study software evolution.This dissertation takes a scientific perspective to model the dynamics of software evolution, and verify the model by simulation.Empirical studies of software evolution have discovered many emergent phenomena, such as the power law distributions in different metrics of software systems and the complex network of relationships among software components.By reviewing the literature, we found similar phenomena in other fields too, as well as generative mechanisms proposed to account for the phenomena.A model of software evolution that incorporates preferential attachment and self-organized criticality (SOC) is proposed in this thesis research and the simulation runs using this model reproduce several emergent phenomena in software evolution.To further explore how individual developers' local changes accumulate to produce high-level phenomena, and to explore the possible causes of log-normal behavior at the body of the commit size distribution, we propose another model based on agents to simulate the interaction between developers and a manager.This simulation shows that power law distributions can emerge from low-level changes without explicit preferential attachment process, and the lower-end of commit size distribution may be shaped by log-normal task size.This dissertation research reveals that large software changes are inevitable in software evolution, and the change size follows a heavy-tailed distribution, making it very difficult to estimate.The simulations also show that large changes are not necessarily caused by significant external factors; the power law structure of software systems can also lead to large changes, as part of the power law change size

Fault diagnosis of mine ventilator based on improved BP neural network

In view of characteristics of complicated correlation of mine ventilator failure and symptom, a fault diagnosis method using BP neural network optimized by dynamic adaptation cuckoo search algorithm was proposed. The optimal initial parameters of neural network are solved by using global search ability of dynamic adaptation cuckoo search algorithm. Then, the BP neural network is trained to obtain the final fault diagnosis model. The example analysis results show that the method can effectively achieve fault diagnosis of mine ventilator and has the characteristics of fast convergence and high precision, and the diagnosis accuracy of the test sample is 92.5%

an empirical study on bug assignment automation using chinese bug data

Univ SE Calif, Ctr Syst & Software Engn, ABB, Microsoft Res, IEEE, ACMSIGSOFT, N Carolina State Univ Comp SciBug assignment is an important step in bug life-cycle management. In large projects, this task would consume a substantial amount of human effort. To compare with the previous studies on automatic bug assignment in FOSS (Free/Open Source Software) projects, we conduct a case study on a proprietary software project in China. Our study consists of two experiments of automatic bug assignment, using Chinese text and the other non-text information of bug data respectively. Based on text data of the bug repository, the first experiment uses SVM to predict bug assignments and achieve accuracy close to that by human triagers. The second one explores the usefulness of non-text data in making such prediction. The main results from our study includes that text data are most useful data in the bug tracking system to triage bugs, and automation based on text data could effectively reduce the manual effort

Injection by Hydrostatic Pressure in Conjunction with Electrokinetic Force on a Microfluidic Chip

A simple method was developed for injecting a sample on a cross-form microfluidic chip by means of hydrostatic pressure combined with electrokinetic forces. The hydrostatic pressure was generated simply by adjusting the liquid level in different reservoirs without any additional driven equipment such as a pump. Two dispensing strategies using a floating injection and a gated injection, coupled with hydrostatic pressure loading, were tested. The fluorescence observation verified the feasibility of hydrostatic pressure loading in the separation of a mixture of fluorescein sodium salt and fluorescein isothiocyanate. This method was proved to be effective in leading cells to a separation channel for single cell analysis

a case study on usage of a software process management tool in china

Nowadays, commercial or in-house customized process management tools have been prevalently adopted for supporting software project management and process improvement. In this paper we report a case study to empirically investigate and evaluate the usage status and implications of a supporting tool named QONE in industrial environment in China. Decision theory is adopted in study design. The analysis is mainly based on the usage data from a typical industrial project. Further questionnaires and follow-up interviews with the end-users are also conducted. The analysis results reveal that 1) the effects of such supporting tool vary with respect to different task types, 2) tasks with smaller granularity are comparatively easier to predict and control, 3) missing data reporting analysis helps to reveal opportunities for further process improvement and tool enhancement. This investigation aims to help us take advantages of such supporting tools and benefit software development eventually

Does Bug Prediction Support Human Developers? Findings From a Google Case Study

Abstract—While many bug prediction algorithms have been developed by academia, they’re often only tested and verified in the lab using automated means. We do not have a strong idea about whether such algorithms are useful to guide human developers. We deployed a bug prediction algorithm across Google, and found no identifiable change in developer behavior. Using our experience, we provide several characteristics that bug prediction algorithms need to meet in order to be accepted by human developers and truly change how developers evaluate their code. I