Bounded Guaranteed Algorithms for Concave Impurity Minimization Via Maximum Likelihood

Partitioning algorithms play a key role in many scientific and engineering disciplines. A partitioning algorithm divides a set into a number of disjoint subsets or partitions. Often, the quality of the resulted partitions is measured by the amount of impurity in each partition, the smaller impurity the higher quality of the partitions. In general, for a given impurity measure specified by a function of the partitions, finding the minimum impurity partitions is an NP-hard problem. Let $M$ be the number of $N$-dimensional elements in a set and $K$ be the number of desired partitions, then an exhaustive search over all the possible partitions to find a minimum partition has the complexity of $O(K^M)$ which quickly becomes impractical for many applications with modest values of $K$ and $M$. Thus, many approximate algorithms with polynomial time complexity have been proposed, but few provide bounded guarantee. In this paper, an upper bound and a lower bound for a class of impurity functions are constructed. Based on these bounds, we propose a low-complexity partitioning algorithm with bounded guarantee based on the maximum likelihood principle. The theoretical analyses on the bounded guarantee of the algorithms are given for two well-known impurity functions Gini index and entropy. When $K \geq N$, the proposed algorithm achieves state-of-the-art results in terms of lowest approximations and polynomial time complexity $O(NM)$. In addition, a heuristic greedy-merge algorithm having the time complexity of $O((N-K)N^2+NM)$ is proposed for $K<N$. Although the greedy-merge algorithm does not provide a bounded guarantee, its performance is comparable to that of the state-of-the-art methods. Our results also generalize some well-known information-theoretic bounds such as Fano's inequality and Boyd-Chiang's bound.Comment: 13 pages, 6 figure

Comparison of two methods in multi-criteria decision-making: application in transmission rod material selection

Transmission rod is an indispensable part in diesel and gasoline engines. Its job is to convert rotation into translational motion or vice versa. The transmission rod material selection plays a very important role, affecting its working function and durability. This study was conducted to compare two Multi Criteria Decision Making (MCDM) methods in transmission rod material selection. They are PIV (Proximity Indexed Value) method, and FUCA (Faire Un Choi Adéquat) method. Seven types of steel commonly used in transmission rods were reviewed for ranking, inclusive of: 20&nbsp;steel, 40&nbsp;steel, 45&nbsp;steel, 18Cr2Ni4WA steel, 30 CrMoA steel, 45Mn2 steel and 40CrNi steel. Nine parameters were used as criteria to evaluate each steel including minimum yield strength, ultimate tensile strength, minimum elongation ratio, contraction ratio, modulus of elasticity, mean coefficient of thermal expansion, thermal conductivity, specific thermal capacity, and density. The weights of the criteria were calculated using three methods inclusive of MEAN weight method, Entropy weight method and MEREC weight method (Method based on the Removal Effects of Criteria). Each MCDM method was combined with the three weight methods mentioned above to rank the alternatives. The obtained results show that when using both PIV and FUCA methods to rank the alternatives, the best and worst alternatives are found regardless of the weight of the criteria. The best alternative determined using the PIV method is also the best alternative determined using the FUCA method. It means that the two PIV and FUCA methods have been shown to be equally effective. Among the seven transmission rod materials reviewed, 20&nbsp;steel was identified as the best, and 40CrNi steel was identified as the wors

An Efficient Spectral Leakage Filtering for IEEE 802.11af in TV White Space

Orthogonal frequency division multiplexing (OFDM) has been widely adopted for modern wireless standards and become a key enabling technology for cognitive radios. However, one of its main drawbacks is significant spectral leakage due to the accumulation of multiple sinc-shaped subcarriers. In this paper, we present a novel pulse shaping scheme for efficient spectral leakage suppression in OFDM based physical layer of IEEE 802.11af standard. With conventional pulse shaping filters such as a raised-cosine filter, vestigial symmetry can be used to reduce spectral leakage very effectively. However, these pulse shaping filters require long guard interval, i.e., cyclic prefix in an OFDM system, to avoid inter-symbol interference (ISI), resulting in a loss of spectral efficiency. The proposed pulse shaping method based on asymmetric pulse shaping achieves better spectral leakage suppression and decreases ISI caused by filtering as compared to conventional pulse shaping filters

Calculation of axial mode separation of a semiconductor laser from reflectance spectrum

It is reported that the axial mode separation of a semiconductor laser can be computed from the reflectance spectrum of a narrow spectral range near the lasing frequency. The Kramers-Kronig dispersion relation is used in this computation. GaAs semiconductor laser is taken as an example. The computed values of the normalized frequency separation for GaAs at lasing photon energy of 1.38 eV range from 0.107 to 0.111 for various widths of the reflectance spectrum. These results are in good agreement with the measured ones

Enhancement of the Tracking Performance for Robot Manipulator by Using the Feed-forward Scheme and Reasonable Switching Mechanism

Robot manipulator has become an exciting topic for many researchers during several decades. They have investigated the advanced algorithms such as sliding mode control, neural network, or genetic scheme to implement these developments. However, they lacked the integration of these algorithms to explore many potential expansions. Simultaneously, the complicated system requires a lot of computational costs, which is not always supported. Therefore, this paper presents a novel design of switching mechanisms to control the robot manipulator. This investigation is expected to achieve superior performance by flexibly adjusting various strategies for better selection. The Proportional-Integral-Derivative (PID) scheme is well-known, easy to implement, and ensures rapid computation while it might not have much control effect. The advanced interval type-2 fuzzy sliding mode control properly deals with nonlinear factors and disturbances. Consequently, the PID scheme is switched when the tracking error is less than the threshold or is far from the target. Otherwise, the interval type-2 fuzzy sliding mode control scheme is activated to cope with unknown factors. The main contributions of this paper are (i) the recommendation of a suitable switching mechanism to drive the robot manipulator, (ii) the successful integration of the interval type-2 fuzzy sliding mode control to track the desired trajectory, and (iii) the launching of several tests to validate the proposed controller with robot model. From these achievements, it would be stated that the proposed approach is effective in tracking performance, robust in disturbance-rejection, and feasible in practical implementation

From Disfluency Detection to Intent Detection and Slot Filling

We present the first empirical study investigating the influence of disfluency detection on downstream tasks of intent detection and slot filling. We perform this study for Vietnamese -- a low-resource language that has no previous study as well as no public dataset available for disfluency detection. First, we extend the fluent Vietnamese intent detection and slot filling dataset PhoATIS by manually adding contextual disfluencies and annotating them. Then, we conduct experiments using strong baselines for disfluency detection and joint intent detection and slot filling, which are based on pre-trained language models. We find that: (i) disfluencies produce negative effects on the performances of the downstream intent detection and slot filling tasks, and (ii) in the disfluency context, the pre-trained multilingual language model XLM-R helps produce better intent detection and slot filling performances than the pre-trained monolingual language model PhoBERT, and this is opposite to what generally found in the fluency context.Comment: In Proceedings of INTERSPEECH 202

Help or Hurt? The Impact of ESG on Firm Performance in S&P 500 Non-Financial Firms

The paper aims to investigate the impact of ESG practice on firms’ financial performance in the context of U.S. market from 2018 to 2020. The paper examines a sample of 57 U.S. non-financial firms belonging to the S&P 500. The Two-Stage Least Squares (2SLS) estimation is employed with an instrumental variable - the political views of the states where the studied firms are located. The paper shows that having a better practice of ESG could enhance firms’ financial performance measured by ROA, ROE, and TobinQ. These findings are consistent with the stakeholder-focused theory instead of shareholder-focus perspective. In addition, the magnitude of the influence of the ESG practice on TobinQ is significantly higher than that of the ESG-ROA and ESG-ROE relations. It reveals that the ESG benefits could make the firms appear more attractive to investors, creating higher market values of the firms’ assets and then higher TobinQ ratio. Not as the TobinQ enhancement, the significant improvement in ROA and ROE would be realized in the long run rather than short term. The low managerial ownership in the U.S. market may increase the chance of ESG overinvestment by the firms’ managers, hence reducing firm value. However, under the pressure of the investors’ strong demand for socially responsible investing, the U.S. firms tend to become involved in ESG activities, obtaining a strong stakeholder commitment and thus creating additional firm value in the long run

NGHIÊN CỨU MÂU THUẪN VÀ LỰA CHỌN ƯU TIÊN TRONG QUY HOẠCH TỔNG HỢP KHÔNG GIAN VEN BIỂN HUYỆN HẢI HẬU - NGHĨA HƯNG TỈNH NAM ĐỊNH

Hai Hau - Nghia Hung are two coastal districts in the Southeast of Nam Dinh province with total area of 35,652.29 km2. Located in the middle between the Southern provinces of the Red river delta and the North Central provinces, Hai Hau and Nghia Hung are about 100 km from Hanoi along National Route 1A and 80 km from Hai Phong, in an area directly affected by the Hanoi - Hai Phong - Quang Ninh growth triangle. The two districts have an approximately 47 km coastline accounting for over 65% of the coastline of the province. Along the coastline there are four rivers: Red river, So river, Ninh Co river and Day river emptying into the sea through the estuaries: Ba Lat, Ha Lan, Ninh Co and Day, which facilitate the development in industry, agriculture, sea ports, trade, tourism... This is also a region with high-speed economic development and a series of plannings. Thus, a number of conflicts in exploiting and using natural resources and environmental protection have been raised, leading to destroyed sceneries, lost ecological balance, and becoming an anxious problem. This paper presents experimental results in defining the conflicts and priorities between sectors and economic fields in integrated coastal space planning of Hai Hau - Nghia Hung districts to select the economic sectors that have the most potential and advantages. Therefore, it will be appropriate in space usage in exploiting and using natural resources and environmental protection, which will provide the basis for the development of a sustainable marine economy.Hải Hậu - Nghĩa Hưng là huyện ven biển nằm ở phía Đông Nam của tỉnh Nam Định có tổng diện tích tự nhiên 35.652,29km2; Nằm ở vị trí trung chuyển giữa các tỉnh phía Nam đồng bằng sông Hồng với các tỉnh Bắc Trung bộ và trong vùng ảnh hưởng trực tiếp của tam giác tăng trưởng Hà Nội-Hải Phòng-Quảng Ninh, Hải Hậu - Nghĩa Hưng chỉ cách Hà Nội theo quốc lộ 1A gần 100 km và cách Hải Phòng trên 80 km; với đường bờ biển dài khoảng 47km chiếm trên 65% chiều dài bờ biển toàn tỉnh; dọc chiều dài đường biển có 4 con sông: Sông Hồng, sông Sò, sông Ninh Cơ và sông Đáy đổ ra biển qua các cửa sông: Ba Lạt, Hà Lạn, Ninh Cơ và cửa Đáy thuận lợi cho phát triển công nghiệp, nông nghiệp, cảng biển, thương mại, du lịch,….đây cũng là khu vực có tốc độ phát triển kinh tế nhanh với hàng loạt quy hoạch nên khu vực này đang nảy sinh các xung đột gây nên những mâu thuẫu trong khai thác sử dụng tài nguyên thiên nhiên và bảo vệ môi trường dẫn đến cảnh quan bị phá vỡ, cân bằng sinh thái bị mất đi và đang trở thành vấn đề đáng quan ngại. Bài báo trình bày kết quả xác định thử nghiệm những vấn đề mâu thuẫn, ưu tiên giữa các nhóm ngành, lĩnh vực kinh tế trong quy hoạch tổng hợp không gian ven biển huyện Hải Hậu - Nghĩa Hưng nhằm lựa chọn các lĩnh vực kinh tế có tiềm năng, thế mạnh để tổ chức một cách hợp lý trong sử dụng không gian trong khai thác, sử dụng tài nguyên thiên nhiên và bảo vệ môi trường tạo cơ sở cho phát triển một nền kinh tế biển bền vững

Active fault-tolerance of the unmanned aerial vehicle automatic control systems

This paper presents an introductory overview of principles of the three-layer hierarchy of active fault-tolerance, providing, determination of the fault type with as many details as enough to get recoverable fault reason and failure toleration by flexible redundancy using; the conception of active fault-tolerant control in abnormal modes is described. Developed models and methods of a systematic approach to fault tolerance in the direction of the effective use of the signal, parametric and structural redundancies and selection of parrying tools. Performed experimental researches of the unmanned aerial vehicle (UAV) automatic control systems (ACS)

A Survey on Some Parameters of Beef and Buffalo Meat Quality

A survey was carried out on 13 Vietnamese Yellow cattle, 14 LaiSind cattle and 18 buffalos in Hanoi to estimate the quality of longissimus dorsi in terms of pH, color, drip loss, cooking loss and tenderness at 6 different postmortem intervals. It was found that the pH value of longissimus dorsi was not significantly different among the 3 breeds (P>0.05), being reduced rapidly during the first 36 hours postmortem, and then stayed stable. The value was in the range that was considered to be normal. Conversely, the color values L*, a* and b* tended to increase and also stable at 36 hours postmortem, except that for LaiSind cattle at 48 hours. According to L* scale, the meat of Yellow and LaiSind cattle met the normal quality but the buffalo meat was considered to be dark cutters. The tenderness of longissimus dorsi was significantly different among the breeds (P<0.05). The value was highest at 48 hours and then decreased for LaiSind and buffalo, but for Yellow cattle the value decreased continuously after slaughtering In terms of tenderness buffalo meat and Yellow cattle meat were classified as “intermediate”, while LaiSind meat was out of this interval and classified as “tough”. Drip loss ratio was increased with the time of preservation (P<0.05). The cooking loss ratio was lowest at 12 hours and higher at the next period, but there was no significant difference among the periods after 36 hours postmotem.Peer reviewe