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THE Funk Gerat 10 equipment is the latest standardized type, and is installed in all the later bombers and reconnaissance machines of the Luftwaffe.

THE art of navigating any mobile craft depends essentially on being able to determine the position of that craft with relation to a fixed point or points; the position may either be obtained in the form of a bearing on, and a distance from, any known fixed point, or of simultaneous bearings from two or more fixed points, which bearings are laid off on a chart and denote, by their intersection, the position of the craft at the time.

The purpose of this paper is to develop a novel MEMS vector hydrophone with the key features of smaller size, better consistency, higher sensitivity and directional reception, and to develop a highly effective and economical obstacle avoidance sonar system. Currently, the typical vector hydrophones are resonant vector hydrophones based on the accelerometer, which greatly increases the volume and constrains the detection sensitivity. Also, because the system is composed of a number of devices, its size is difficult to be reduced.

A novel double T-shape MEMS vector hydrophone is proposed with a fish’s lateral line organs as prototypes. The structure size and layout location of the piezoresistors were determined by simulation analysis, and the double T-shape microstructure was fabricated integrally by MEMS manufacturing technology, after which, the acoustic package of the microstructure was completed and the prototype was produced. Finally, the packaged hydrophone was calibrated in a standing wave field in the first-class national-defense underwater acoustic calibration station of China. Also, the design and test of an obstacle avoidance sonar system based on the vector hydrophone were completed.

The calibration data show that the double T-shape vector hydrophone has a flat frequency response curve, exhibits a sensitivity of −180 dB (1 kHz, 0 dB reference 1 V/uPa) and shows a good directivity pattern in the form of an “8” shape. The test results of the obstacle avoidance sonar system further verify the feasibility of detecting underwater acoustic signals.

The next work is to increase the sensitivity by optimizing the microstructure and to realize orientation by organizing array.

The hydrophone has the advantages of smaller size, lower cost and directional reception. It can be used to develop highly effective and economical obstacle avoidance sonar system, thus solving the problems of water transport efficiency and traffic safety. The hydrophone has broad application prospects and a huge market potential in the civilian fields.

The MEMS technology and innovative bionic microstructure enable the miniaturization and low cost of the hydrophone. The hydrophone is easy to form array and can narrow the array aperture greatly. So, the hydrophone can be widely used in civil sonar systems.

The purpose of this paper is to focus on alleviating the problems of both hidden and exposed terminal, which remain unsolved in many directional MAC protocols.

GPS is used to calibrate synchronization among the nodes, and directional antennas are used. In the protocol, different antenna mode and transmit power are used. The assertion signal and omni‐directional RTS are transmitted in omni‐directional mode, while directional CTS, directional RTS, DATA and ACK are transmitted in directional mode. With properly designed RTS‐CTS handshake, the protocol can make full use of spatial reuse of directional communication and enhance parallelism in data transmission.

The preliminary simulation results indicate that the protocol works well and achieves considerably high performance in both sparse and dense ad hoc networks.

The line of sight environment is the main limitation that the MAC protocol will be applied.

The protocol is a very useful solution for employing directional antennas for ad hoc networks.

The MAC protocol can effectively alleviate the directional hidden and exposed terminal problems as well as node deafness. It can greatly improve throughput and achieve low‐medium access delay, making it suitable for ad hoc networks.

The purpose of this paper is to compare the low‐cost switched‐beam antennas and the more expensive adaptive antennas in a wireless mesh network (WMN) scenario.

A mathematical framework is adopted in order to determine, for the two antenna systems, the number of sustainable simultaneous communications and the achievable throughput of a backbone WMN in a realistic outdoor environment.

The paper includes a thorough examination of benefits and crucial implementation issues concerning the adoption multiple antennas on mesh routers.

The paper investigates the relationship between the antenna system and the adopted channel coding technique, to determine the set‐up that may offer the best compromise between performance and complexity.

The purpose of this paper is to propose a new method to achieve omni-directional vibration vector signal acquisition, and use this method to improve the accuracy of the underground explosion point localization.

Following an introduction, this paper describes the design principle of a sensor structure, and discusses the rationality of the spherical structure of the sensor through finite element analysis. The sensor prototype is designed according to the above method, and its performance is tested by the sensor calibration experiment. Finally, applications are also discussed.

This paper shows that the method for underground omni-directional vibration signal acquisition is reasonable and feasible. The vibration sensor, designed by this method, of which the triaxial dynamic characteristics are consistent, and the three-dimensional vibration information acquired by this sensor can achieve high-precision localization for an underground explosion point.

The paper describes a new method for omni-directional vibration vector signal acquisition. The vibration sensor is developed based on this method, which has a broad application prospect in the positioning of an underground explosion point, the evaluation of explosive power and other underground projects.

During the academic session 1991/92, a project was carried out to review the strategic and operational management of the staffed public information points in the Library and Information Services at Aston University. Three main methods were used: an analysis of enquiries; a staff attitudes survey; and a customer survey. The main results which emerged were that staff perceived that there was no‐one with overall management responsibility for the service that an on‐going training programme for information point staff should be introduced; and that most customers were satisfied with the existing quality of service and approachability of the staff. Consequently, the Head of Information Services has assumed strategic and operational responsibility for the service; a rolling training programme for staff has been introduced; and a Quality Circle has been established to formulate a Customer Care Policy, and to produce recommendations for continuous improvement of the service.

Traditional expatriate predeparture training has been general in nature, neglecting the input of the respective host country workforce (HCW) in identifying specific work interaction demands for optimizing expatriate management performance. This study found that workforces from Mexico, Indonesia and the USA differed significantly in their perceptions of both positive and negative behaviors affecting their work performance. Accordingly, the paper calls for a significant change in research and practice to incorporate the voice of the HCW to develop more valid and effective predeparture training for expatriate managers to enhance their performance in the host country to which they are assigned.

The purpose of this paper is to examine the concept of translation equivalence in extant research on translation in accounting: What is the equivalence that is expected of translation, and how is it assumed to come into being? This paper presents a coherent, theoretically informed approach to how different views on equivalence are connected to the objective of international comparability in financial accounting and how related, often-underlying assumptions intertwine in this discussion.

This paper takes an interdisciplinary approach by utilizing equivalence theories from the discipline of translation studies. It canvasses two dichotomy-like approaches – natural versus directional equivalence and formal versus dynamic equivalence – to compose a theoretical framework within which to analyze 25 translation-related papers discussing accounting harmonization published from 1989 to 2018.

This paper presents evidence of theoretical contradictions likely to affect the development of translation research in accounting if they go unrecognized. Moreover, the analysis suggests that these contradictions are likely to originate in the assumptions of mainstream accounting research, which neglect both the constructed nature of equivalence and the socially constructed nature of accounting concepts.

Despite the significance of translation for the objective of international comparability, this paper is the first comprehensive theoretical approach to equivalence in accounting research. It responds to a recognized demand for studying equivalence and its limitations, challenges many of the expectations accounting research places on translation and discusses the possible origins of related assumptions.

This paper analyzes the connectedness with network among the major cryptocurrencies, the G7 stock indexes and the gold price over the coronavirus disease 2019 (COVID-19) pandemic period, in 2020.

This study used a multivariate approach proposed by Diebold and Yilmaz (2009, 2012 and 2014).

For a stock index portfolio, the results of static connectedness showed a higher independence between the stock markets during the COVID-19 crisis. It is worth noting that in general, cryptocurrencies are diversifiers for a stock index portfolio, which enable to reduce volatility especially in the crisis period. Dynamic connectedness results do not significantly differ from those of the static connectedness, the authors just mention that the Bitcoin Gold becomes a net receiver. The scope of connectedness was maintained after the shock for most of the cryptocurrencies, except for the Dash and the Bitcoin Gold, which joined a previous level. In fact, the Bitcoin has always been the biggest net transmitter of volatility connectedness or spillovers during the crisis period. Maker is the biggest net-receiver of volatility from the global system. As for gold, the authors notice that it has remained a net receiver with a significant increase in the network reception during the crisis period, which confirms its safe haven.

Overall, the authors conclude that connectedness is shown to be conditional on the extent of economic and financial uncertainties marked by the propagation of the coronavirus while the Bitcoin Gold and Litecoin are the least receivers, leading to the conclusion that they can be diversifiers.

本文分析於2020年2019冠狀病毒病肆虐期間、主要的加密貨幣、七國集團 (G7) 股價指數與黃金價格三者之間在網絡上的連通性。

分析使用迪博爾德和耶爾馬茲 (Diebold and Yilmaz (2009, 2012, 2014)) 提出的多變量分析法。

就一個股票指數投資組合而言,靜態連結的結果顯示、在2019冠狀病毒病肆虐期間,股票市場之間有更高的獨立性。值得我們注意的是:一般來說,加密貨幣在股票指數投資組合起著多元化投資作用,這可減低不穩定性,尤其是在危機時期。動態連結的結果與靜態連結的結果沒有顯著的分別。我們剛提到、比特幣黃金已成為純接收者。除了處於先前水平的達世幣和比特幣黃金外,就大部分的加密貨幣而言,連通的範圍在衝擊後都得以維持。事實上,在這危機時期,比特幣一直是波動性連結或溢出的最大淨傳播者。掛單者 (Maker) 是從全球系統中出現的最大波動淨接收者。至於黃金,我們注意到在危機時期、它仍然是在網絡接收方面擁有顯著增長的淨接收者,這確認其為安全的避難所。

總的來說,我們的結論是:連通性被確認為取決於標誌著受廣泛傳播的冠狀病毒影響下的經濟和金融欠缺穩定的程度,而比特幣黃金和萊特幣則是最小的接收者,這帶出一個結論、就是:比特幣黃金和萊特幣、可以成為多元化投資項目。