Joint optimization of LORA and spares stocks considering corrective maintenance time

Level of repair analysis（LORA） is an important method of maintenance decision for establishing systems of operation and maintenance in the equipment development period. Currently, the research on equipment of repair level focuses on economic analysis models which are used to optimize costs and rarely considers the maintenance time required by the implementation of the maintenance program. In fact, as to the system requiring high mission complete success, the maintenance time is an important factor which has a great influence on the availability of equipment systems. Considering the relationship between the maintenance time and the spares stocks level, it is obvious that there are contradictions between the maintenance time and the cost. In order to balance these two factors, it is necessary to build an optimization LORA model. To this end, the maintenance time representing performance characteristic is introduced, and on the basis of spares stocks which is traditionally regarded as a decision variable, a decision variable of repair level is added, and a multi-echelon multiindenture（MEMI） optimization LORA model is built which takes the best cost-effectiveness ratio as the criterion, the expected number of backorder（EBO） as the objective function and the cost as the constraint. Besides, the paper designs a convex programming algorithm of multi-variable for the optimization model, provides solutions to the non-convex objective function and methods for improving the efficiency of the algorithm. The method provided in this paper is proved to be credible and effective according to the numerical example and the simulation result.

Mission-oriented dynamic optimization model of carrying spares for warship redundant system

Redundancy is a common structure for warship system,and it is an effective way to improve the reliability of the system.In this paper, warship system is taken as the object of study,based on the system reliability equivalence principle, a spares demand rate calculation method for redundant system is proposed through structure transformation. According to the system analysis method, the general modeling data structure of spares support echelon and system indenture is established, and the mission success probability is taken as the optimization target to build the dynamic optimization model of carrying spares during the process of multi-phase. By introducing the Lagrange multiplier, the spares weight, volume and cost are transformed to the single target of the spares total scale, and the initial Lagrange factors and its dynamic adjustment policy is proposed. In a given example, the main influence factors of the carrying spares project are analyzed, and the study results are in accordance with the reality, which can provide a new approach to mission-oriented carrying spares optimization for the redundant system.

Mission-Oriented Configuration Model of Aircraft Carrying Spares and Dynamic Optimization Policy

Spare parts are critical to scheduled maintenance and fault repair, and can directly affect the readiness and combat capability of equipment. Equipmentrs capacity of carrying spares is influenced by its storage space and scales, so it is necessary to consider economic factors, e.g. spares cost, as well as non-economic ones, such as spares volume, mass and scale, when optimizing spares configuration. Aiming at this problem, the optimization model based on multi-constraints for carrying spares is built by METRIC theory and system analysis. Through the introduction of Lagrange factors, the spares cost is transformed to shadow price, and the optimization method for carrying spares and the dynamic adjustment policy of Lagrange factors are proposed. The result of a given example is analyzed, and demonstrates that the proposed model can be optimized with all constraints, and the research can provide a new way for carrying spares optimization.

Study to Cost of Air Spares Support Based on IPSO

Air spares support is general term of using and repairing of aircrafts which is the material foundation of aero technical support, its effectiveness influences operational effectiveness and equipments of aircrafts directly. Based on particle swarm optimization algorithm, a new model is proposed to optimize the distribution of the cost of air spares, it take the funds as resource and the improvement of performance efficiency as objective and deduces the expressions to get the best distribution plan. The results of experiments indicate that this model can make full use of the limited funds and obtain the highest efficiency of air spares support.

A Bound Heuristic Technique for Solving DRAMA Spares Optimizations

This paper studies the solution technique to solve the DRAMA spares allocation optimization problem. DRAMA model is an analytic spare optimization model of a multi-item, multi-location, and two-echelon inventory system. The computation of its system spares availability is much complicated. The objective function and constraint functions of DRAMA model could be written as the separable forms. A new bound heuristic algorithm has been presented by improving the bound heuristic algorithm for solving the reliability redundancy optimization problem (BHA in short). With the results, the proposed algorithm has been found to be more economical and effective than BHA to obtain the solutions of large DRAMA model. The new algorithm could be used to solve reliability redundancy optimization problems with the separable forms.

Confidence Level of System Spares OptimizationUsing Fuzzy Theory

To obtain a higher readiness for a complex system, the common method is to store some spares. Confidence level of system spares is an important parameter to control the probability of the spares required. By introducing fuzzy theory, this paper allocates the confidence level of system spares to its subsystems, thus to achieve a rational management of system spares,

An Optimal Replacement Policy for a System with Finite Spares

This paper develops a new replacement policy for a system with multiple spare units.An optimal replacement period is determined by maximizing the mean time to failure of the system.We show that there exists a finite and unique optimal replacement period T for units with strictly increasing failure rates. We also proof that the optimal repIacement period for a system with spares is decreasing in k. Furthermore, an algorithm is presented to get the optimal replacement period and a numerical example is given to illustrate the result. with strictly

New Approach to Calculate the Unavailability of Identical Spares in Cold Spare Configuration

Cold spare is the most common configuration amongst the three types of configuration for systems used on board and for power generation systems. A new approach to calculate the unavailability of systems composed of identical spares in cold spare configuration was proposed in this study. Instead of using the spare gate of dynamic fault tree( DFT) and the Markov analysis,AND gate of static fault tree used for calculating the unavailability of cold spare systems was proposed in this paper. By using this approach,unavailability of identical cold spare systems composed of nonrepairable spare components can be calculated exactly and systems composed of both repairable and nonreparable identical spare components can be estimated without building large Markov state diagram.

Configuration model of partial repairable spares under batch ordering policy based on inventory state

Rational planning of spares configuration project is an effective approach to improve equipment availability as well as reduce life cycle cost （LCC）. With an analysis of various impacts on support system, the spares demand rate forecast model is constructed. According to systemic analysis method, spares support effectiveness evaluation indicators system is built, and then, initial spares configuration and optimization method is researched. To the issue of discarding and con-sumption for incomplete repairable items, its expected backorders function is approximated by Laplace demand distribution. Combining the （s-1, s） and （R, Q） inventory policy, the spares resup-ply model is established under the batch ordering policy based on inventory state, and the optimi-zation analysis flow for spares configuration is proposed. Through application on shipborne equipment spares configuration, the given scenarios are analyzed under two constraint targets：one is the support effectiveness, and the other is the spares cost. Analysis reveals that the result is consistent with practical regulation;therefore, the model＇s correctness, method＇s validity as well as optimization project＇s rationality are proved to a certain extent.

Fertility preservation in patients with gynecologic cancer

In this editorial we comment on the article by Gu et al.We focus and debate the necessity of fertility sparing surgery in young women’s with gynecologic cancers,specifically on those patients with the desire to conceive.This type of individu-alized treatment options is often very difficult,due to the risk of disease evolution and multiple disparities in fertility preservation services among women in di-fferent countries and societies.For this reason national policy interventions are mandatory in order to ensure equitable access this procedures,in women with cancer.

Epigenetic combined with transcriptomic analysis of the m6A methylome after spared nerve injury-induced neuropathic pain in mice

Epigenetic changes in the spinal cord play a key role in the initiation and maintenance of nerve injury-induced neuro pathic pain.N6-methyladenosine(m6A)is one of the most abundant internal RNA modifications and plays an essential function in gene regulation in many diseases.However,the global m6A modification status of mRNA in the spinal cord at different stages after neuropathic pain is unknown.In this study,we established a neuropathic pain model in mice by preserving the complete sural nerve and only damaging the common peroneal nerve.High-throughput methylated RNA immunoprecipitation sequencing res ults showed that after spared nerve injury,there were 55 m6A methylated and diffe rentially expressed genes in the spinal cord.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway results showed that m6A modification triggered inflammatory responses and apoptotic processes in the early stages after spared nerve injury.Over time,the diffe rential gene function at postoperative day 7 was enriched in "positive regulation of neurogenesis" and "positive regulation of neural precursor cell prolife ration." These functions suggested that altered synaptic morphological plasticity was a turning point in neuropathic pain formation and maintenance.Results at postoperative day 14 suggested that the persistence of neuropathic pain might be from lipid metabolic processes,such as "very-low-density lipoprotein particle clearance," "negative regulation of choleste rol transport" and "membrane lipid catabolic process." We detected the expression of m6A enzymes and found elevated mRNA expression of Ythdf2 and Ythdf3 after spared nerve injury modeling.We speculate that m6A reader enzymes also have an important role in neuropathic pain.These results provide a global landscape of mRNA m6A modifications in the spinal cord in the spared nerve injury model at diffe rent stages after injury.

Repairable Configuration Optimization Model under Two-Echelon Inventory

Spares inventory configuration optimization is an effective way to improve readiness and reduce life cycle cost of equipment.Through analyzing two-echelon spares support system,the METRIC model basic theory was used.An inventory configuration optimization model of two-echelon spares support system was proposed which took the spares expected shortfall as the object and made the minimum repairable parts expected shortfall instead of the maximum spares supportability as the objective function.Marginal efficiency analysis algorithm was applied to optimizing the spares configuration and generating a rational spares inventory configuration.Finally,several examples are given to verify the model.

Organ sparing to cure stage IV rectal cancer: A case report and review of literature

BACKGROUND Rectal sparing is an option for some rectal cancers with complete or good response after chemoradiotherapy(CRT);however,it has never been evaluated in patients with metastases.We assessed long-term outcomes of a rectal-sparing approach in a liver-first strategy for patients with rectal cancer with resectable liver metastases.CASE SUMMARY We examined patients who underwent an organ-sparing approach for rectal cancer with synchronous liver metastases using a liver-first strategy during 2010-2015(n=8).Patients received primary chemotherapy and pelvic CRT.Liver surgery was performed during the interval between CRT completion and rectal tumor re-evaluation.Clinical and oncological characteristics and long-term outcomes were assessed.CASE SUMMARY All patients underwent liver metastatic resection with curative intent.The R0 rate was 100%.Six and two patients underwent local excision and a watch-and-wait(WW)approach,respectively.All patients had T3N1 tumors at diagnosis and had good clinical response after CRT.The median survival time was 60(range,14-127)mo.Three patients were disease free for 5,8,and 10 years after the procedure.Five patients developed metastatic recurrence in the liver(n=5)and/or lungs(n=2).Only one patient developed local recurrence concurrent with metastatic recurrence 24 mo after the WW approach.Two patients died during follow-up.CONCLUSION The results suggest good local control in patients undergoing organ-sparing strategies for rectal cancer with synchronous liver metastasis.Prospective trials are required to validate these data and identify good candidates for these strategies.

Robot-Assisted Nephrotomy as a Nephron-Sparing Approach for Completely Intraparenchymal Renal Tumors

Introduction: The diagnosis of small renal masses and the endophytic tumor approach have become challenging. This study aims to describe exclusively robot-assisted surgery as an alternative nephron-sparing approach for renal intraparenchymal tumors. Patients and Methods: We retrospectively analyzed all patients with completely endophytic tumors undergoing robot-assisted partial nephrectomy, treated under the Da Vinci System®, aided by intraoperative ultrasound. The patients’ demographic characteristics, perioperative and oncological outcomes were assessed. Results: From a total of 13 partial nephrectomies performed between 06/2010 and 10/2021, all patients underwent nephrotomy. The patients’ mean age was 52 years and the tumor measured mean 2.6 cm. Warm ischemia time was 24 minutes and histopathological analysis revealed that 12 patients had renal cell carcinoma. In a mean 36-month follow-up, no significant renal function alterations were found and no local or systemic recurrences occurred. Conclusion: Robot-assisted access is a safe and effective option for the nephron-sparing technique in completely intraparenchymal renal tumors.

Dynamic Prediction Method for Valuable Spare Parts Demand in Weaponry Equipment Based on Data Perception

Missile is an important weapon system of the army.The spare parts of missile equipment are significant effect on military operations.In order to improve the mission completion rate of missile equipment in wartime,this paper introduces data sensing method to forecast the demand of valuable spare parts of missile equipment dynamically.Firstly,the information related to valuable spare parts of missile equipment was obtained by data sensing,and the sample size was determined by Bernoulli uniform sampling probability.Secondly,according to the data quality of multi-source and multi-modal,the data requirement for dynamic demand prediction of valuable spare parts of missile equipment was obtained.Finally,according to the characteristics of the spare parts,the life of the spare parts was predicted,realizing the dynamic prediction of the demand for valuable spare parts of missile equipment.The results show that the demand of valuable spare parts of missile equipment can be predicted dynamically by using this method,the accuracy is higher than 95%,and the real-time performance is more excellent.

协同过滤系统的矩阵稀疏性问题的研究

应用奇异值算法得到一个无缺失的矩阵,引进了一种增强的、基于参数的Pearson相关系统算法来提高相关性算法的准确性。提出一个基于奇异值分解和增强Pearson系数的"HybridSVD"算法,用MovieLens数据集来评价该算法,并和其他经典的传统算法做了比较。实验结果证明,"HybridSVD"算法比其他传统算法能更好地处理协同过滤中的稀疏性问题。

Muscle-sparing切口在胸部手术中的应用

目的探讨胸部Muscle-sparing切口在临床中的应用价值。方法采用Muscle-sparing切口开胸手术56例,其中周围型肺癌行肺叶切除术39例,随机抽取同期39例肺癌患者及其他病变行后外侧切口开胸手术病例共计56例作为对照组;对两组病例术后切口疼痛、术侧肩关节功能等指标进行分析。术后肩关节功能的评估采用Constant评分法;术后切口疼痛的评估采用Prince-Henry评分法。结果治疗组术后3天、1周、4周切口疼痛程度明显低于对照组;术侧肩关节功能明显优于对照组。治疗组无围术期死亡,术后无皮下积液、切口血肿发生。结论有选择地应用Muscle-sparing切口,可以在保证手术质量和的安全性的前提下,减轻术后切口疼痛,减少术后肩关节功能障碍。

普通高校田径队课余洲练的研究与实践

普通高校学生课余田径训练是一个完整、复杂、多层次的教学过程。大学生在校以文化课学习为主。课余时间训练，其训练特点既不同于专业队，也有别于少年体校。因此，探索课余田径训练的规律性，构建符合高校实际的最佳模式，是迅速提高运动成绩的有力举措。本文在高等院校课余田径训练的运动员选材、训练时间安排、运动负荷、训练周期安排等方面，进行了归纳和阐述。

Radionuclide Colloid ^(32)P Used for the Treatment of Stage II Lung Cancer by Video Enhanced Minimal Access Muscle Sparing Thoracotomy

Objective: To study the feasibility of radionuclide colloid 32P used for the treatment of stage II lung cancer by video enhanced minimal access muscle sparing thoracotomy (VEMAST). Methods: Video assisted thoracoscopic surgery (VATS) was carried out under general anesthesia. A double lumen endobronchial tube was intubated into trachea. One lung ventilation of the healthy side was done during operation. An incision of 8–10 cm long was made along the 4th or 5th intercostals. The lobectomy could be performed under VATS. Radionuclide colloid 32P was injected locally into the area where surgical cleaning of lymph node around was considered to be unsatisfactory or desection of the tumor was not completed. Results: The operation with VEMAST was successful in 29 patients. A conventional lobectomy by thoracotomy had to be done due to unusual bleeding from the pulmonary artery involved during VEMAST in one case and the procedure was interrupted because the pulmonary artery cloud not be separated from the tumor in another patient. There was no dead case or the patient who had any severe complication or adverse response to the radiant. Conclusion: Radionuclide therapy was performed to the treatment of stage II lung cancer with VEMAST in case that surgical resection was considered not to be satisfactory. Minithoractomy assisted with VATS lobectomy and radionuclide colloid 32P therapy is a safe and e?ective technique for some selected stage II lung cancer.

保留胸部肌肉的侧方开胸切口36例临床分析

目的评价腋下Muscle—sparing切口，即保留胸部肌肉的侧方开胸切口的优点。方法主要是通过对背阔肌及前锯肌的移动和拉开后显露骨性胸廓后进胸。结果全组切口长度（13．5±1．5）cm，进胸时间平均13min，关胸时间平均15min。全组切口均达甲等愈合。入胸失血量均〈50ml，患者术后1—3d肩关节活动度恢复到术前状态，胸部疼痛轻微，切口愈合平整，外形美观，术后平均住院日比常规开胸少1．5d。结论腋下Muscle—sparing切口具有创伤小、出血少、术后恢复快以及外形美观的特点，值得推广。