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Air traffic control is an important tool to ensure the safety of civil aviation. For the departments that do the work of air traffic control, reducing the percentage of unsafe event is the core task of safety management. If the relationship between the percentage of unsafe event and their influencing factors can be effectively clarified, then the probability of unsafe event in some control department can be predicted. So, it is of great importance to improve the level of safety management. To quantitatively estimate the probability of unsafe event, a three-layer BP neural network model is introduced in this paper. First, a probabilistic representation of unsafe event related to air traffic control department is made, and then, the probability of different classes of unsafe events and safe events is taken as the outputs of the BP neural network, the factors influencing occurrence of unsafe event connected with air traffic control is taken as inputs, and the sigmoid function is chosen as activation function for the hidden layer. Based on the error function of neural network, it is proved that the general BP neural network has two drawbacks when used for the training of small probability events, which are as follows: the pattern does not ensure that the sum of probability of all events is equal to one and the relative error between the actual outputs and desired outputs is very large after the training of neural network. The reason proved in this paper is that the occurrence rate of the unsafe event is much smaller than that of the safe event, resulting in each weight in the hide layer being subjected to the desired outputs of the safe event when using the gradient descent method for network training. To address this issue, a new mapping method is put forward to reduce the large difference of the desired outputs between the safe event and unsafe event. It is theoretically proved that the mapping method proposed in this paper can not only improve the training accuracy but also ensure that the sum of probability is equal to one. Finally, a numeric example is given to demonstrate that the method proposed in this paper is effective and feasible.

The production planning and control of aircraft remanufacturing system is becoming a critical issue with the development and application of reusable aircraft parts. With the unpredictable demands of remanufactured products, the aircraft parts remanufacturing system (APRS) operates with various disruptions, which could seriously influence the system's efficiency. To generate timely and efficient response towards the frequent disruptions in APRS, an adaptive rescheduling policy is presented in this paper with a trigger and a re-scheduler. The trigger evaluates the system performance loss caused by the disruptions with a specific Relative Performance Deviation Index (RPDI) and determines when the re-scheduler is activated to re-optimize the schedule. The re-scheduler then intelligently selects the optimal rescheduling method by an improved random forest (IRF) based on the system status described by a set of reduced but important features. In order to deal with the data imbalance in different classes in the remanufacturing system, this paper develops a problem-oriented conditional generative adversarial networks (CGAN) for data augmentation. Aiming to demonstrate the effectiveness of the proposed method, an experiment is conducted with three commonly used classification approaches. And, the results show the competitiveness of the proposed approach in reducing the rescheduling trigger times and the rescheduling performance improvement.

Subduction of the Paleo-Pacific and Mongol–Okhotsk oceanic plates is widely believed to have caused extensive Mesozoic magmatism and lithospheric deformation in East Asia. However, it remains unclear how the two tectonic domains affected NE China, and whether a boundary exists between them, because the Songnen Block in central NE China is covered by sedimentary rocks and the related mafic magmatism has been rarely discovered. Here we report a suite of Early Jurassic (ca. 175 Ma) mafic volcanic rocks (including basalt and basaltic andesite) from the Sk2 Borehole, Songliao Basin, NE China. The Sk2 mafic rocks are characterized by high Th/U, Zr/Y and Ti/Y ratios, and their geochemical signatures are consistent with formation in a back-arc extensional setting, rather than an arc setting. The rocks show depleted zircon eHf(t) and whole-rock eNd(t) values, which are comparable to mafic rocks located on the east of the Songliao Basin. This suggests that they both have a depleted mantle source, unlike the mafic rocks on the west of the Songliao Basin with relatively enriched Nd and Hf isotopes. Early–Middle Jurassic mafic rocks are distributed in the Erguna Block, >500 km to the west from the Sk2 Borehole, whereas coeval mafic rocks are widely distributed in the nearby eastern Heilongjiang and Jilin provinces. These intraplate-like mafic rocks and the Early Jurassic bimodal rocks within the Lesser Xing'an and Zhangguangcai ranges likely formed in response to lithospheric extension that was triggered by subduction of the Paleo-Pacific Plate. The Early Jurassic mafic rocks directly underlie the oldest sedimentary rocks (the Huoshiling Formation) in the Songliao Basin, which suggests that basin formation was probably initiated by lithospheric extension.

A set of atmospheric optical communication system is introduced in this paper. The study of atmospheric optical communication has experienced more than 10 years of troughs. There are some problems that cannot be solved. For example, phase fluctuations produce optical scintillation. There is still no good solution. There are some enterprise applications that optical fiber communication cannot meet the requirements. It is proposed that optical fiber communication is replaced by atmospheric optical communication. To this end, a lot of manufacturers have developed this type of atmospheric optical communication system. Because there is no market, a large number of production lines are closed. There is another type of atmospheric optical communication system. Its application is to study the nature of atmospheric optics. The main customers are research institutes, laboratories, universities and other research groups. At present, the system of this kind of application on the market is very little. The author has developed a set of such a system. It is a portable atmospheric optical communication system. In this paper, the structure of the system is introduced in detail. In the development of the interface and the array receiver, 3D printing technology is used.

In the previous paper, the author puts forward a new technique called aperture averaging weight factor shifting. This technique is created against the disadvantages of the traditional receiver for atmospheric optical communication. This new type of receiver is called the Y-type receiver. A set of Y-type receiver is developed. In this paper, the author introduces the design ideas and hardware of the Y-type receiver. 3D printing technology is also employed in developing the Y-type receiver.

An unmanned aerial vehicle electro-optical pod developed by the author is introduced in this paper. This instrument is created by using 3D printing technology. This unmanned aerial vehicle will be used in the field of free-space optical communication. At present, building up a free-space optical communication experimental link requires a huge resource. It also needs mutual cooperation. This limits the development of free-space optical communication technology. And there is almost no research on the free-space optical communication link between the ground and the unmanned aerial vehicle. Independent development of equipment in this link is of great significance. This paper is the result of originality: develop unmanned aerial vehicle electro-optical pod by the use of 3D printing technology and build up ground-to-space link.

Large and complex equipment reliability evaluation is extremely dependent on equipment reliability experiment data, maintenance records, and failure data. With the informationalization and intellectualization of equipment (such as CNC machine tools, shield machines, and weaponry), large amounts of data (big data) will be produced during the equipment's operation. Abundant data provide a strong support for equipment operational reliability analysis in the industrial big data age, but also pose a huge challenge for reliability analysis. This paper first explores the opportunities provided by big data to promote the reliability analysis and assessment of complex equipment. Then, we mainly focus on the remaining challenges of equipment operational reliability assessment using the industrial big data method, such as the fact that most of the data reflect an intermediate state (incomplete failure state) of the equipment. We also consider a way to analyze the multiple-states of the equipment operation and correlate the multiple failure modes of the equipment operation using the big data. Moreover, a big data analysis method for calculating the reliability and predicting the residual life of gradual systems is discussed, along with a method for combining the traditional reliability calculation theory with the big data theory. All of these issues provide a significant challenge for the reliability analysis of complex equipment in the big data age.

In free-space optical communication, aperture averaging effect can be used to optimize receiver design. A variety of factors contribute to aperture averaging effect, such as the receiving aperture, the light source, and the turbulence link. Cassegrain system is usually used as the receiver. It is technically feasible to optimally design the light source according to Cassegrain system's aperture averaging function and the turbulent propagation path. The aperture averaging functions of Cassegrain system and single aperture system are analyzed in this paper. The results show that the average aperture function of Cassegrain system decreases significantly. Large obscuration ratio can significantly reduce the value of K 0 function.

Aperture averaging effect can smooth the optical signal fluctuations. Generally, the aperture function is assumed to be a single circle when its aperture averaging function K 0 is calculated. In recent years, K 0 function of a complex receiving aperture is also discussed. Actually, Cassegrain system is usually used as a telescope for free-space optical communication. There is a little bit difference from the previous analysis when Cassegrain system is used to analyze aperture averaging effect. K 0 function of Cassegrain system is analyzed in this paper. The calculation result can be used to establish simulation model for optical propagation system.

A singular aperture receiver is usually used in a free-space optical communication system. To increase the received optical flux, a larger diameter receiver is preferred, but this approach causes a sharp increase in cost. It also limits the large-scale civil use of free-space optical communications. This paper proposes a technique called aperture averaging weight factor shifting and designs a new type of receiver that can greatly reduce the cost of a free-space optical communication system. This paper offers a comparative analysis of two types of receivers for optical scintillation and proves theoretically that using this new type of receiver does not degrade the performance.

In this paper, a new kind of method is developed to analyse the bit-error rate for a free-space optical communication system, which is based on the three most important parameters of scintillation statistics, i.e. fraction of time of fade and surge, mean frequency of level crossings, and mean duration of fade and surge. By using this method, the relationship between the bit-error rate and scintillation is clearly identified. The tip-tilt error deteriorates the performance of a free-space optical communication system. Fine tracking ability of adaptive optics ( through tip-tilt compensation) can overcome this difficulty. The fade and surge statistical parameters with tip-tilt compensation are evaluated for the plane wave model. The bit-error rate as a function of the scintillation statistical parameters ( with tip-tilt compensation) is developed. The results show that the bit-error rate is reduced notably through tip-tilt compensation for free-space optical communication.

Mixed mode placement (MMP) problem can be successfully solved by combining floorplanning and cell based placement according to circuit's hierarchy. Floorplanning is the key design stage for achieving optimum performance if virtual blocks (VB: Soft Block) in floorplanning are not restricted to only have rectangular shapes. In this paper, an effective floorplanning algorithm RSF used in MMP is presented to perform the rectilinear-shaped optimization for VBs. Our approach allows VBs to transform into rectilinear shapes without overlaps and selects the optimum shapes for them during topology optimization of normal floorplanning. It is based on the dead-space block assignment and pin allocation during the process of packing. It depends on the theoretic analysis on lower bound of net wire length in half perimeter mode which makes RSF result in shorter total wire length in floorplanning. Applied in MMP, RSF can improve the final performance of MMP.

In this paper, an efficient partitioning algorithm for mixed-mode placement, extended-MFFC-based partitioning, is presented. It combines the bottom-up clustering and the top-down partitioning together, using the algorithm of extended-MFFC-based clustering and the partitioning package of HMETIS. To do this, we can not only cluster cells considering logic dependency but also partition them aiming at min-cut. Good experimental results prove that extended-MFFC-based partitioning performs well in mixed-mode placement with big pre-designed blocks. We also give the comparison between HMETIS and our partitioning to prove its remarkable function in mixed-mode placement.

The rapid increase of complexity in System-on-a-Chip design urges the design community to raise the level of abstraction beyond RTL. Automated behavior-level and system-level synthesis are naturally identified as next steps to replace RTL synthesis and will greatly boost the adoption of electronic system-level (ESL) design. High-level executable specifications, such as C, C++, or SystemC, are also preferred for system-level verification and hardware/software co-design.

Fractional motion estimation (FME) on sub-pixels will occupy almost over 45% of the computation complexity of H.264 encoding process. Therefore a high performance VLSI architecture of FME is described in this paper to achieve the capacity of encoding the high-resolution real-time video stream for HDTV. Our design is improved from an existing work by involving a pipeline strategy in sub-pixel interpolation unit which can avoid the long delay paths in 6-tap ID FIR so as to increase the clock frequency up to 200MHz. Moreover, a 16-pixel search engine is adopted to remove the redundant interpolation area and parallelize the various block size search which can save more than half of the clock cycles in processing a macro block. Our design is implemented with only 189K gates at operating frequency of 200MHz in worst case (285MHz in typical case). It can provide the processing capacity of more than 250K MB/sec which is enough for 1080HD (1920/spl times/1088) video streams at frame rate of 30fps. It is a useful intellectual property (IP) design for multimedia system.

System-in-silicon (SiS) is a multi-chip architecture to realize wide bandwidth communication between logic and memory with low power. The application of SiS to H.264/AVC motion estimation is presented. DRAM is integrated with 23.1 Gb/s bandwidth and 1.6pJ/b data transfer efficiency, realizing real-time 1080HDTV processing with 263.1GB/s. The authors present a system-in-silicon architecture with 1024b inter-chip bus to provide high-bandwidth low-power connectivity between logic and memory. The highly parallel architecture also allows low frequency (25MHz) operation while achieving real-time motion estimation for 1080HDTV. The solution achieves the required 23.1 Gb/s bandwidth and associated processing for motion estimation at a power level of 190mW

Mixed mode placement (MMP) is characterized by a number of same-height standard cells mixed with scattering big blocks in a fixed die. The variety of size and number of blocks introduces challenges to existing algorithms in achieving reasonable solution quality and running time. A new design flow named recursive mixed mode placement (RMMP) is presented in this paper to provide a solution of MMP with this circuit's variety of block configuration taken into account. It starts from recursively partitioning circuits to form a tree of virtual blocks in the different condition of the size and number of blocks as well as the logical or physical hierarchy. Then it combines floorplan on block level and quadratic place (Q-place) on cell level to complete the global placement. Our approach takes advantage of combining floorplan and Q-place algorithms to fit the variety of circuit's components. The combined approach improves the algorithm efficiency and obtains satisfactory results of MMP in terms of wire length and running time on various industry and academia test cases.

As more data-path stacks are integrated into system-on-a-chip (SOC), data-path is becoming a critical part of the whole giga-scale integrated circuits (GSI) design. The traditional layout design methodology can not satisfy the data-path performance requirements because it has no knowledge of the data-path bit-sliced structure and the strict performance (such as timing, coupling, and crosstalk) constraints. In this paper, we address fundamental problems in layout design automation of data-path. We concentrate on the key technologies in data-path layout design. We also discuss the corresponding researches and solutions in this research field.

As more and more functions and operations are integrated into system-on-a-chip (SOC), data-path is becoming a critical part of the whole giga-scale integrated circuits (GSI) design. But the traditional placement tool cannot obtain satisfied result of data-path circuit because it has no knowledge of the data-path bit-slice structure and the parallel constraint. In this paper, an algorithm named DPP will be addressed to handle the standard-cell based data-path placement. It exploits the signal flow of circuit to generate the structure regularity of cells. Then, it converts the bit-slice structure to parallel constraints and partition policy so as to enable Q-Place algorithm on the placement. The design flow and the main algorithms will be introduced. Finally, the paper will discuss the satisfied experimental result of the tool compared with the Cadence placement tool SE.

Considering the efficiency and veracity of rules-based OPC applied to recent large-scale layout, we firstly point out the importance of the selection and creation of rules in rules-based OPC. Our discussion addresses the crucial factors in selecting and creating rules as well as how we select and create more concise and practical rules-base. Based on our ideas we suggest four primary rules and as a result we show some rule data in table. The automatic construction of the rules-base called OPCL is an important part of the whole rules-based OPC software.

As the feature sizes of integrated circuits have been continually reducing to below exposure wavelength, some correcting techniques, such as OPC and PSM are indispensable to compensate for the distortions on wafer images. In this paper, we describe an object-based approach to OPC named OPCM, which is a model-based OPC tool. Also, a rule-based OPC has been adopted to enhance the practicability of the software.