针对MTO(Make To Order)生产模式下,设备故障带来的拖期交货和产品质量下降等问题,建立了以最小化拖期惩罚成本和最大化产品合格率为优化目标的设备维护与柔性作业车间调度问题集成优化模型。提出了一种新的层次生物地理算法进行求解,...针对MTO(Make To Order)生产模式下,设备故障带来的拖期交货和产品质量下降等问题,建立了以最小化拖期惩罚成本和最大化产品合格率为优化目标的设备维护与柔性作业车间调度问题集成优化模型。提出了一种新的层次生物地理算法进行求解,算法将解空间分为上、下两层,设计了分层迭代寻优机制,融入多种局域搜索策略,提高了收敛速度和寻优精度。与遗传算法和生物地理学优化算法对比,计算结果表明层次生物地理算法优于其他两种算法。展开更多
Research of the acoustic local effect of metamaterial is widely used in the fields of environmental science,military industry and biomedicine.In this paper,the metamaterial is designed by annular columnar structures.T...Research of the acoustic local effect of metamaterial is widely used in the fields of environmental science,military industry and biomedicine.In this paper,the metamaterial is designed by annular columnar structures.The acoustic local effect in slender columnar structure with two layers of rings in air is investigated.Results prove that when the plane acoustic wave is incident into the model,complex interference and diffraction occur.And at different frequencies,multipolar acoustic local effect existes and cycle distribution phenomenon is observed.It is noteworthy that this phenomenon has very weak relatedness with the materials and acoustic parameters of the model.The research of this metamaterial design in this paper has definite reference significance in the acoustic communication and amplification of the acoustic signal detection.展开更多
A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 5...A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 55 nm were synthesized via the Turkevich method and were then immobilized onto the surface of an uncladded sensor probe using a polydopamine layer. To obtain a sensor probe with high sensitivity to changes in the refractive index, a set of key optimization parameters, including the sensing length, coating time of the potydopamine layer, and coating time of the gold nanoparticles, were investigated. The sensitivity of the optimized sensor probe was 522.80 nm per refractive index unit, and the probe showed distinctive wavelength shifts when the refractive index was changed from 1.328 6 to 1.398 7. When stored in deionized water at 4 ℃, the sensor probe proved to be stable over a period of two weeks. The sensor also exhibited advantages, such as low cost, fast fabrication, and simple optical setup, which indicated its potential application in remote sensing and real-time detection.展开更多
In this paper, a new MAC protocol for WLAN is proposed. The new protocol, which is called PRMA (Priority Rotation Multiple Access), is based on priority rotation theory. In PRMA, each access cycle consists of a conten...In this paper, a new MAC protocol for WLAN is proposed. The new protocol, which is called PRMA (Priority Rotation Multiple Access), is based on priority rotation theory. In PRMA, each access cycle consists of a contention period and a data transmission period. During contention period, a node competes for the right to control the channel according to its priority. The winner of contention can control the channel and can send data without collision in data transmission period. Analysis and simulation results show that PRMA is a stable protocol, which means that it can achieve high throughput both under high-load and under low-load conditions.展开更多
A plastic surface-relief grating as a wavelength division multiplexer is designed and fabricated with the conventional mould pressing technique using the transmission-type fused quartz phase grating as mask pattern an...A plastic surface-relief grating as a wavelength division multiplexer is designed and fabricated with the conventional mould pressing technique using the transmission-type fused quartz phase grating as mask pattern and polycarbonate as basal material.The experiment results show that in an optimizing process,the plastic surface-relief grating has the highest firstorder diffraction efficiency under adequate groove depth and incident angle,and can be used as the best optical path for wavelength division multiplexing(WDM).We also establish the experiment setup for testing the WDM performance of the plastic surface-relief grating based wavelength division multiplexer.The results show that the proposed wavelength division multiplexer has the high-stability temperature characteristics,the low insertion loss of less than 5 dB,the large isolation of greater than 20 dB,the low polarization-dependent loss(PDL) of less than 0.4 dB and the relatively steep pass-band characteristics.It is a WDM device with good performance,which can be applied in short distance communication.展开更多
Traditional 802.11 power saving mechanism (PSM) treats multicast and broadcast traffic equally, and suffers sig-nificant performance degradation with multicast background traffic. This paper proposes an enhanced PSM t...Traditional 802.11 power saving mechanism (PSM) treats multicast and broadcast traffic equally, and suffers sig-nificant performance degradation with multicast background traffic. This paper proposes an enhanced PSM that effectively dif-ferentiates multicast streams. It re-arranges the virtual bitmap of the traffic indication map (TIM) to carry traffic status for mul-ticast groups and introduces a concept of sequential transmission of multi-addressed data to facilitate differentiation among mul-ticast groups. Our analysis shows that the enhanced PSM can effectively save power in mixed traffic environments.展开更多
文摘针对MTO(Make To Order)生产模式下,设备故障带来的拖期交货和产品质量下降等问题,建立了以最小化拖期惩罚成本和最大化产品合格率为优化目标的设备维护与柔性作业车间调度问题集成优化模型。提出了一种新的层次生物地理算法进行求解,算法将解空间分为上、下两层,设计了分层迭代寻优机制,融入多种局域搜索策略,提高了收敛速度和寻优精度。与遗传算法和生物地理学优化算法对比,计算结果表明层次生物地理算法优于其他两种算法。
基金National Natural Science Foundation of China(No.61671414)Natural Science Foundation for Young Scientists of Shanxi Province,China(No.201601D202035)
文摘Research of the acoustic local effect of metamaterial is widely used in the fields of environmental science,military industry and biomedicine.In this paper,the metamaterial is designed by annular columnar structures.The acoustic local effect in slender columnar structure with two layers of rings in air is investigated.Results prove that when the plane acoustic wave is incident into the model,complex interference and diffraction occur.And at different frequencies,multipolar acoustic local effect existes and cycle distribution phenomenon is observed.It is noteworthy that this phenomenon has very weak relatedness with the materials and acoustic parameters of the model.The research of this metamaterial design in this paper has definite reference significance in the acoustic communication and amplification of the acoustic signal detection.
基金Supported by the Ministry of Science and Technology of China(No.2012YQ090194)the National Natural Science Foundation of China(No.51473115)
文摘A fast and facile method of fabricating fiber-optic localized surface plasmon resonance sensors baseff on spherical gold nanoparticles was introduced in this study. The gold nanoparticles with an average diameter of 55 nm were synthesized via the Turkevich method and were then immobilized onto the surface of an uncladded sensor probe using a polydopamine layer. To obtain a sensor probe with high sensitivity to changes in the refractive index, a set of key optimization parameters, including the sensing length, coating time of the potydopamine layer, and coating time of the gold nanoparticles, were investigated. The sensitivity of the optimized sensor probe was 522.80 nm per refractive index unit, and the probe showed distinctive wavelength shifts when the refractive index was changed from 1.328 6 to 1.398 7. When stored in deionized water at 4 ℃, the sensor probe proved to be stable over a period of two weeks. The sensor also exhibited advantages, such as low cost, fast fabrication, and simple optical setup, which indicated its potential application in remote sensing and real-time detection.
文摘In this paper, a new MAC protocol for WLAN is proposed. The new protocol, which is called PRMA (Priority Rotation Multiple Access), is based on priority rotation theory. In PRMA, each access cycle consists of a contention period and a data transmission period. During contention period, a node competes for the right to control the channel according to its priority. The winner of contention can control the channel and can send data without collision in data transmission period. Analysis and simulation results show that PRMA is a stable protocol, which means that it can achieve high throughput both under high-load and under low-load conditions.
基金supported by the Natural Science Foundation of Fujian Province of China (No.2011J01353)
文摘A plastic surface-relief grating as a wavelength division multiplexer is designed and fabricated with the conventional mould pressing technique using the transmission-type fused quartz phase grating as mask pattern and polycarbonate as basal material.The experiment results show that in an optimizing process,the plastic surface-relief grating has the highest firstorder diffraction efficiency under adequate groove depth and incident angle,and can be used as the best optical path for wavelength division multiplexing(WDM).We also establish the experiment setup for testing the WDM performance of the plastic surface-relief grating based wavelength division multiplexer.The results show that the proposed wavelength division multiplexer has the high-stability temperature characteristics,the low insertion loss of less than 5 dB,the large isolation of greater than 20 dB,the low polarization-dependent loss(PDL) of less than 0.4 dB and the relatively steep pass-band characteristics.It is a WDM device with good performance,which can be applied in short distance communication.
基金Project (Nos. 60574087 and 60721003) supported by the National Natural Science Foundation of China
文摘Traditional 802.11 power saving mechanism (PSM) treats multicast and broadcast traffic equally, and suffers sig-nificant performance degradation with multicast background traffic. This paper proposes an enhanced PSM that effectively dif-ferentiates multicast streams. It re-arranges the virtual bitmap of the traffic indication map (TIM) to carry traffic status for mul-ticast groups and introduces a concept of sequential transmission of multi-addressed data to facilitate differentiation among mul-ticast groups. Our analysis shows that the enhanced PSM can effectively save power in mixed traffic environments.
