Complexity results for scheduling chains on a single machine

We investigate the computational complexity of deterministic sequencing problems in which unit-time jobs have to be scheduled on a single machine subject to chain-like precedence constraints. NP-hardness is established for the cases in which the number of late jobs or the total weighted tardiness is to be minimized, and for several related problems involving the total weighted completion time criterion.     

Exact solution of a simple finite infinite source interaction model

Networks of queues with finite and infinite source customers have been used to study the interaction between the batch jobs and interactive jobs in computer systems. Earlier Kaufman ([1], PP-345-348) developed accurate approximations for a simple nonproduct form network of this type. In this paper we offer exact solutions for the same model with one finite source customer. We study both FIFO and LIFO disciplines at the contention node. The results are derived for the case where the finite source think time and service time distributions are generalized hyperexponential.     

A mixed integer linear programming approach to minimize the number of late jobs with and without machine availability constraints

This study investigates scheduling problems that occur when the weighted number of late jobs that are subject to deterministic machine availability constraints have to be minimized. These problems can be modeled as a more general job selection problem. Cases with resumable, non-resumable, and semi-resumable jobs as well as cases without availability constraints are investigated. The proposed efficient mixed integer linear programming approach includes possible improvements to the model, notably specialized lifted knapsack cover cuts. The method proves to be competitive compared with existing dedicated methods: numerical experiments on randomly generated instances show that all 350-job instances of the test bed are closed for the well-known problem 1|_ri|∑_wiUi$1|r_i|\sum w_i{U}_i$. For all investigated problem types, 98.4% of 500-job instances can be solved to optimality within 1 hour.     

Volatile Organic Compounds and Physiological Parameters as Markers of Potato (Solanum tuberosum L.) Infection with Phytopathogens

The feasibility of early disease detection in potato seeds storage monitoring of volatile organic compounds (VOCs) and plant physiological markers was evaluated using 10 fungal and bacterial pathogens of potato in laboratory-scale experiments. Data analysis of HS-SPME-GC-MS revealed 130 compounds released from infected potatoes, including sesquiterpenes, dimethyl disulfide, 1,2,4-trimethylbenzene, 2,6,11-trimethyldodecane, benzothiazole, 3-octanol, and 2-butanol, which may have been associated with the activity of Fusarium sambucinum, Alternaria tenuissima and Pectobacterium carotovorum. In turn, acetic acid was detected in all infected samples. The criteria of selection for volatiles for possible use as incipient disease indicators were discussed in terms of potato physiology. The established physiological markers proved to demonstrate a negative effect of phytopathogens infecting seed potatoes not only on the kinetics of stem and root growth and the development of the entire root system, but also on gas exchange, chlorophyll content in leaves, and yield. The negative effect of phytopathogens on plant growth was dependent on the time of planting after infection. The research also showed different usefulness of VOCs and physiological markers as the indicators of the toxic effect of inoculated phytopathogens at different stages of plant development and their individual organs.     

“边缘”境地的别样风景—林莽早期诗歌创作及其与新时期文学话语关系探究

白洋淀诗歌群落成员、朦胧诗人林莽创作于特定复杂时代语境的早期诗歌,沉郁凄婉、温厚中和、节制内敛而又不乏现代派色彩与思想锋芒,具有独特的艺术个性和审美价值。然而在新时期诗歌史乃至新时期文学史上却一度被边缘化而处于“失踪”的境地。考察林莽早期诗歌创作及其“失踪”的成因,有助于较为全面地认识1970年代至新时期初诗歌创作的丰富性,更好地理解把握林莽早期诗歌创作与新时期文学话语范式之间的复杂关系,为重新审视新时期文学主流话语提供一个参照。     

清末民初中国侦探小说中的传统性因素

在传统的文学史叙述中,明清以来的公案小说在进入晚清以后常常被描述为逐步衰落,且渐渐被舶来的侦探小说所取代,这一过程的形象说法是“包拯与福尔摩斯交接班”。但与此同时,我们却常常忽略了公案小说/侠义公案小说对清末民初中国侦探小说的潜在/显在影响。比如这一时期中国侦探小说中“传奇”而非科学的情节因素、公差而非私家侦探的人物身份、传统侠客形象的影子、以小说教化读者的创作目的,乃至于作者本身的“民族主义”倾向等等。而这些中国传统的文学、文化因素,既构成了诸如刘鹗《老残游记》、吴趼人《中国侦探案》和刘半农“老王探案”等清末民初“侦探小说”文本内部的“混乱”与复杂之所在,又内在规定了此后民国侦探小说发展道路中的本土性思想资源和文类特征。     

In‐situ characterization of the early stage of pipeline steel corrosion in bicarbonate solutions by electrochemical atomic force microscopy

An electrochemical atomic force microscope was used to characterize the early stage of corrosion of an X100 pipeline steel in bicarbonate solutions with varied concentrations by synchronous measurements of electrochemical potential of the steel and its topographic evolution with time. Upon immersion of the steel in 0.01 M NaHCO₃ solution, both electrochemical potential and topographic profile are associated with the dissolution of air‐formed oxides present on the steel surface. The potential drops and the surface roughness increases rapidly. When corrosion of the steel occurs, the potential further drops and the surface roughness of the steel increases gradually. As the steel corrosion achieves a steady state, the generation of corrosion products reaches a dynamic equilibrium state. The surface roughness maintain an approximately stable value. In solutions containing increased bicarbonate concentrations, such as 0.1 M and 0.5 M NaHCO₃, the steel can be passivated. The formed passive film can eliminate some surface features and improves the surface roughness. The topographic profile of the steel surface in 0.5 M NaHCO₃ solution is smoother than that in 0.1 M solution. The surface features within 20 nm become eliminated after 4500 s of immersion in 0.1 M NaHCO₃ solution, while larger features within 50 nm in size are eliminated in 0.5 M NaHCO₃ solution in the same time period. Copyright © 2016 John Wiley & Sons, Ltd.     

广东省社会稳定监测指标体系与预警方法研究

社会稳定监测与预警是创造、保持和谐社会的重要手段.根据社会稳定理论研究的相关成果,在初步遴选8大类73个指标的基础上,通过聚类分析选定12个指标构建社会稳定监测指标体系,并提出了基于3σ控制原理的社会稳定预警方法.通过对广东省社会稳定状况进行实证分析,结果表明广东省未来5年社会稳定基本上处于可控状态.     

Tomographic imaging of incipient dental-caries using optical coherence tomography and comparison with various modalities

We present the optical coherence tomography (OCT) made to investigate the early dental caries in human teeth and compare its results with those taken by conventional imaging modalities including light illuminating examination (LIE), digital intra-oral radiography (DIOR), and electron probe micro analyzer (EPMA). Morphological features and caries-involved areas of the dental structure were mainly investigated by LIE, DIOR, and OCT to study the infection of the caries lesion in pits and fissures. The biochemical information acquired with EPMA and the morphological features taken with OCT in the early stage of caries were compared and analyzed to present an objective and practical index for the degree of caries. The experimental results allow us to conclude that OCT could be used to provide quantitative analysis of caries based on the reflectivity difference in the specimen.     

Clay: An important raw material for prehistoric man

Early techniques of making pottery can be investigated by ⁵⁷Fe Mössbauer spectroscopy. Iron is generally present in unpurified clays in concentrations of several percent. During firing, the iron undergoes characteristic changes of its chemical and physical state, depending on the kiln atmosphere and on the maximum firing temperature reached. These changes can be followed by Mössbauer spectroscopy. Firing techniques can often be reconstructed when spectra of laboratory and field fired samples are compared with those observed in ancient sherds.