A New Approach of Dynamic Clustering Based on Particle Swarm Optimization and Application in Image Segmentation

This paper presents a new approach of dynamic clustering based on improved Particle Swarm Optimization (PSO) and which is applied to image segmentation (called DCPSONS). Firstly, the original PSO algorithm is improved by using diversity mechanism and neighborhood search strategy. The improved PSO is then combined with the well-known data clustering k-means algorithm for dynamic clustering problem where the number of clusters has not yet been known. Finally, DCPSONS is applied to image segmentation problem, in which the number of clusters is automatically determined. Experimental results in using sixteen benchmark data sets and several images of synthetic and natural benchmark data demonstrate that the proposed DCPSONS algorithm substantially outperforms other competitive algorithms in terms of accuracy and convergence rate

Cooperative Group In Current Vietnamese Commercial Environment

Purpose: The article researches the compatibility between the cooperative group and the current commercial environment in Vietnam to propose for improvement to the laws and for promotion of development of the cooperative group.   Theoretical framework: Recent literature points out that the cooperative group model is quite suitable for the production and business psychology of citizens in Vietnam. In the current stage of development, however, from the influence and impact of international integration and the increasingly fierce competitive pressure of various types of enterprises, the cooperative group have encountered many difficulties to survive. On the other hand, in the context of judicial reform in Vietnam, the issue of complete law system and expanding the freedom to business has always been paid special attention by the Party and Vietnam State.   Design/methodology/approach: The authors have combined traditional research methods of legal science such as legal analysis method, legal efficiency assessment method and legal comparison method.   Findings: According to research, the cooperative group is well adapted to Vietnam's commercial environment because it is compatible with investor psychology and meets the conditions and circumstances of nature, economy and society. However, since Vietnam's deep integration with the rest of the world, the cooperative group model has faced numerous difficulties and challenges, and if suitable solutions are not found, it is very likely that this collective economy will become increasingly difficult. As a result, the article suggests some important solutions, such as offering cooperative group legal status and requiring more preferential lending policies with long loan terms, simple and quick loan procedures, and easy team cooperation.   Research, Practical & Social implications: This research may support many develop future research in Vietnam.   Originality/value: The study of the freedom to business become more and more urgent and very important in Vietnam

Síntesis de interpolación de los controladores para un sistema de accionamiento eléctrico multimotor que contiene un elemento enlazado elásticamente

Partial differential equations, integral, differential, or other equations describe multi-motor automatic electric drive systems containing elastic conveyor belts. Because of the elastic and distributive nature of the system parameters, the transfer function describing them is often a complex expression, containing not only the arguments as a linear system but also the inertial and transcendental components. This makes the precise control of tension and speed synchronously much more complicated than the centralized parameter system. A promising numerical solution based on the real interpolation method will simplify the procedure for synthesizing control loops while preserving the characteristic properties of objects with distributed parameters. The objective of the study is to propose a feasible solution for synthesizing the regulators based on the real interpolation method; it allows direct operation with the original transfer function containing the inertial and transcendental components. In this paper, we proposed an approach to synthesize the control system for objects with distributed parameters using the real interpolation method to reduce computational capacity and synthesis error while preserving the properties of this object class. Building an experimental model of the two-motor electric drive system containing an elastic conveyor to verify the effectiveness of the proposed algorithm. The simulation and experimental results indicate that the control system with the received regulators operating stably and meets the required quality criteria. It proves the efficiency of the synthesis algorithm based on the real interpolation method.Introducción: los sistemas de accionamiento eléctrico multimotor que incluyen transportadores elásticos son un ejemplo de sistemas típicos con parámetros distribuidos descritos por ecuaciones complejas. Debido a la naturaleza elástica y distributiva de los parámetros del sistema, la función de transferencia que los describe suele ser una expresión compleja que contiene los componentes inercial y trascendental. Problema: la naturaleza elástica y distributiva de los parámetros del sistema hace que el control preciso de la tensión y la velocidad sincrónicamente sea mucho más complicado que el sistema de parámetros centralizados. Metodología: se propone una solución numérica para sintetizar los reguladores basada en el método de interpolación real para reducir la capacidad computacional y el error de síntesis preservando las propiedades características de los objetos con parámetros distribuidos. Conclusión: la eficacia del algoritmo propuesto se verifica mediante un modelo experimental del sistema de accionamiento eléctrico de dos motores que contiene un transportador elástico. Los resultados de simulación y experimentales indican que el sistema de control con los reguladores recibidos opera de manera estable y cumple con los criterios de calidad requeridos. Originalidad: los resultados de la investigación se pueden aplicar en el desarrollo de sistemas centrales de control y monitoreo para líneas de producción automáticas con sistemas de accionamiento multimotor que incluyen transportadores

Assessing the Potential of Climate Smart Agriculture in Large Rice Field Models in Vietnam

This study assesses the economic, social, and environmental impacts of Large Field Models (LFMs) and their potential for promoting Climate-Smart Agriculture (CSA). In Vietnam, the government introduced the Large Field Model (LFM), a type of production organization, in which enterprises or cooperatives establish a cooperative relationship with farmers to apply a unification production procedure by providing production inputs (including material and technical support) and/or buying outputs from producers. These LFMs can be classified under three different forms based on the extent of those linkages: (1) farmers contribute land and/or labour to farmer cooperatives; (2) farmers sign contracts with cooperatives or enterprises and receive inputs; and (3) farmers lease out/sell their land to cooperatives or enterprises. Although the key objectives of constructing LFMs come from requirements in improving rice quality and rice production efficiency, these models also have potential for applying CSA to achieve three CSA pillars: productivity, resilience and mitigation. Productivity: the LFMs ensure integration between enterprises and farmers, wherein rice production is promoted, given that the output is sold at a more stable price. Therefore, farmers confidently manage their business to increase productivity. In addition, higher output price and lower production cost is observed from LFMs’ production. Better output price comes from the commitments of enterprises and higher rice quality produced from LFMs. The reduction in production costs is also achieved by taking advantage of economy of scale to apply modern agricultural machinery (such as tractors) and thus reduce labour costs. Resilience: this CSA pillar is created indirectly from LFMs. In general, as farmers use LFMs, they have a better chance to access certified seeds and follow the production procedures of enterprises under the direct support from technicians, and they are less likely to be exposed to disease epidemics than non-participant farmers. In addition, farmers who sign contracts with enterprises/cooperatives or work in LFMs tend to share their knowledge and discuss weather issues with technicians before deciding when to sow or harvest to reduce climate risks. Mitigation: the LFM production contributes to reduced GHG emissions. LFMs created a foundation to apply advanced cultivation methods and to follow strictly modern techniques such as: One Must Five Reductions (1M5Rs), Three Reductions Three Gain (3R3G), 4 Alternate Wetting and Drying (AWD), System of Rice Intensification (SRI), and Deep Fertilizer Placement (DPF). The synchronized irrigation timing or flattened surface field of LFMs also contributes more efficient water use. Moreover, this model changes farmer behaviours toward more efficient and environmentally friendly paddy straw treatment to mitigate environmental impacts. In sum, there are potentials for promoting CSA application in LFMs. The integration developed through LFMs will produce friendly and mutually beneficial networks of farmers to share knowledge and modern techniques. This also encourages farmers to improve cultivating skills and output quality to sustain their contracts with better enterprises in the long run. In addition, the pressure from climate risks will push farmers to act collectively to adapt and mitigate environmental impacts. These potentials should be accompanied by the strong support from the government through its response to climate changes in the Nationally Determined Contribution (NDCs). However, there are still many constraints for expanding CSA application into LFMs. First, traditional cultivation and small landholding habits make it difficult for enterprises to accumulate land to form LFMs. Even when farmers agree to contribute their land to cooperatives, this model is still struggling to establish the appropriate benefit-sharing method in order to keep it working smoothly in the long run, especially due to land price fluctuations. Second, there are infrastructure-related issues. Some types of CSA practices require infrastructure support, for example irrigation systems for applying Alternate Wetting and Drying (AWD). Finally, there is a need for a legal mechanism to bind contracts between enterprises and farmers, especially under high price volatility. Vietnam’s policy system to enhance CSA application and expand LFMs is still characterized by limitations related to effectiveness, validation and public-private participation. This requires a change to attract the participation of local government, enterprises, and farmers. For example, experience from other countries shows that in the case of small scale production, legal measures would not be feasible because of high transaction costs. Therefore, using community value to bind farmers to contracts is the most feasible measure that has been proven. In addition, support for developing agricultural insurance and infrastructure investment is important. However, before expanding CSA application into LFMs, detailed studies of LFMs in each region are required because each model might be more efficient for one specific region with a specific crop

AN UPDATED CHECKLIST AND COMMENTS FOR SECTION PIQUETIA (CAMELLIA, THEACEAE)

New Camellia species in section Piquetia have recently been discovered. It is necessary to enumerate the number of species and update the specific characteristics of this section. Based on the study of more than 30 pieces of literature and a large number of specimens, a total of 15 species belonging to section Piquetia, including two new species, are identified. A taxonomic key to all species is provided, and typical characteristics of the section are also discussed. Information on the distribution, ecology, and conservation status of each species, as well as notes on the differences between closely related species, is also provided.

Secondary Network Throughput Optimization of NOMA Cognitive Radio Networks Under Power and Secure Constraints

Recently, the combination of cognitive radio networks with the nonorthogonal multiple access (NOMA) approach has emerged as a viable option for not only improving spectrum usage but also supporting large numbers of wireless communication connections. However, cognitive NOMA networks are unstable and vulnerable because multiple devices operate on the same frequency band. To overcome this drawback, many techniques have been proposed, such as optimal power allocation and interference cancellation. In this paper, we consider an approach by which the secondary transmitter (STx) is able to find the best licensed channel to send its confidential message to the secondary receivers (SRxs) by using the NOMA technique. To combat eavesdroppers and achieve reasonable performance, a power allocation policy that satisfies both the outage probability (OP) constraint of primary users and the security constraint of secondary users is optimized. The closed-form formulas for the OP at the primary base station and the leakage probability for the eavesdropper are obtained with imperfect channel state information. Furthermore, the throughput of the secondary network is analyzed to evaluate the system performance. Based on that, two algorithms (i.e., the continuous genetic algorithm (CGA) for CR NOMA (CGA-CRN) and particle swarm optimization (PSO) for CR NOMA (PSO-CRN)), are applied to optimize the throughput of the secondary network. These optimization algorithms guarantee not only the performance of the primary users but also the security constraints of the secondary users. Finally, simulations are presented to validate our research results and provide insights into how various factors affect system performance

Community perceptions of social, economic and environmental impacts of flooding in central districts of Hanoi, Vietnam

The impacts of flooding on road infrastructure in Hanoi are highly disruptive, despite recent progress by the Vietnamese authorities in improving the city’s drainage systems. The GCRF–OSIRIS Project aims to optimise investment strategies to minimise the impacts of flood disasters, making disaster risk reduction more effective, by introducing operational research methods. In support of this objective, the project carried out an impact assessment in four of the city’s central districts. The assessment considered locally perceived social, economic and environmental impacts on residents, local entrepreneurs, and on visiting street vendors and transport service providers. Impacts of flooding were found to be highly gender-differentiated. When roads are flooded, women—both resident and visiting—face greater conflicts between the need to maintain their incomes and the responsibilities of caring for vulnerable family members, resulting in increased stress and increasing risks to their health. The assessment suggests that such disproportionate impacts on women could be mitigated through public education and pre-emptive planning measures