Modeling,Simulation,and Risk Analysis of Battery Energy Storage Systems in New Energy Grid Integration Scenarios

Energy storage batteries can smooth the volatility of renewable energy sources.The operating conditions during power grid integration of renewable energy can affect the performance and failure risk of battery energy storage system(BESS).However,the current modeling of grid-connected BESS is overly simplistic,typically only considering state of charge(SOC)and power constraints.Detailed lithium(Li)-ion battery cell models are computationally intensive and impractical for real-time applications and may not be suitable for power grid operating conditions.Additionally,there is a lack of real-time batteries risk assessment frameworks.To address these issues,in this study,we establish a thermal-electric-performance(TEP)coupling model based on a multitime scale BESS model,incorporating the electrical and thermal characteristics of Li-ion batteries along with their performance degradation to achieve detailed simulation of grid-connected BESS.Additionally,considering the operating characteristics of energy storage batteries and electrical and thermal abuse factors,we developed a battery pack operational riskmodel,which takes into account SOCand charge-discharge rate(Cr),using amodified failure rate to represent the BESS risk.By integrating detailed simulation of energy storage with predictive failure risk analysis,we obtained a detailed model for BESS risk analysis.This model offers a multi-time scale integrated simulation that spans month-level energy storage simulation times,day-level performance degradation,minutescale failure rate,and second-level BESS characteristics.It offers a critical tool for the study of BESS.Finally,the performance and risk of energy storage batteries under three scenarios—microgrid energy storage,wind power smoothing,and power grid failure response—are simulated,achieving a real-time state-dependent operational risk analysis of the BESS.

Readmission rate and early complications in patients undergoing total knee arthroplasty:A retrospective study

BACKGROUND Total knee arthroplasty(TKA)can improve pain,quality of life,and functional outcomes.Although uncommon,postoperative complications are extremely consequential and thus must be carefully tracked and communicated to patients to assist their decision-making before surgery.Identification of the risk factors for complications and readmissions after TKA,taking into account common causes,temporal trends,and risk variables that can be changed or left unmodified,will benefit this process.AIM To assess readmission rates,early complications and their causes after TKA at 30 days and 90 days post-surgery.METHODS This was a prospective and retrospective study of 633 patients who underwent TKA at our hospital between January 1,2017,and February 28,2022.Of the 633 patients,28 were not contactable,leaving 609 who met the inclusion criteria.Both inpatient and outpatient hospital records were retrieved,and observations were noted in the data collection forms.RESULTS Following TKA,the 30-day and 90-day readmission rates were determined to be 1.1%(n=7)and 1.8%(n=11),respectively.The unplanned visit rate at 30 days following TKA was 2.6%(n=16)and at 90 days was 4.6%(n=28).At 90 days,the unplanned readmission rate was 1.4%(n=9).Reasons for readmissions included medical(27.2%,n=3)and surgical(72.7%,n=8).Unplanned readmissions and visits within 90 days of follow-up did not substantially differ by age group(P=0.922),body mass index(BMI)(P=0.633),unilateral vs bilateral TKA(P=0.696),or patient comorbidity status(30-day P=0.171 and 90-day P=0.813).Reoperation rates after TKA were 0.66%(n=4)at 30 days and 1.15%(n=8)at 90 days.The average length of stay was 6.53 days.CONCLUSION In this study,there was a low readmission rate following TKA.There was no significant correlation between readmission rate and patient factors such as age,BMI,and co-morbidity status.

Risk factors for recurrence of common bile duct stones after surgical treatment and effect of ursodeoxycholic acid intervention

BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an accurate diagnostic method for choledocholithiasis and treatment option for stone removal.Additionally,ursodeoxycholic acid(UDCA)can dissolve cholesterol stones and prevent their development and reappearance by lowering the cholesterol concen-tration in bile.Despite these treatment options,there are still patients who experience stone recurrence.The clinical data of 100 patients with choledochal stones who were hospitalized at the Yixing People’s Hospital and underwent ERCP for successful stone extraction between June 2020 and December 2022 were retrospectively collected.According to the post-ERCP treatment plan,100 patients were classified into UDCA(n=47)and control(n=53)groups.We aimed to assess the clinical efficacy and rate of relapse in the two patient populations.We then collected information(basic demographic data,clinical characteristics,and serum biochemical indicators)and determined the factors contributing to relapse using logistic regression analysis.Our secondary goal was to determine the effects of UDCA on liver function after ERCP.Compared to the control group,the UDCA group demonstrated a higher clinical effectiveness rate of 92.45%vs 78.72%(P<0.05).No significant differences were observed in liver function indices,including total bilirubin,direct bilirubin,gamma-glutamyl transpeptidase,alanine aminotransferase,alkaline phosphatase,and aspartate aminotransferase,between the two groups before treatment.After treatment,all liver function indices were significantly reduced.Comparing the control vs UDCA groups,the UDCA group exhibited significantly lower levels of all indices(55.39±6.53 vs 77.31±8.52,32.10±4.62 vs 45.39±5.69,142.32±14.21 vs 189.63±16.87,112.52±14.25 vs 149.36±15.36,122.61±16.00 vs 171.33±22.09,96.98±10.44 vs 121.35±11.57,respectively,all P<0.05).The stone recurrence rate was lower in the UDCA group(13.21%)in contrast with the control group(44.68%).Periampullary diverticula(OR:6.00,95%CI:1.69-21.30),maximum stone diameter(OR:1.69,95%CI:1.01-2.85),stone quantity>3(OR:4.23,95%CI:1.17-15.26),and positive bile culture(OR:7.61,95%CI:2.07-27.91)were independent factors that influenced the relapse of common bile duct stones after ERCP(P<0.05).Furthermore,postoperative UDCA was identified as a preventive factor(OR:0.07;95%CI:0.08-0.09).CONCLUSION The intervention effect of UDCA after ERCP for common bile duct stones is adequate,providing new research directions and references for the prevention and treatment of stone recurrence.

Exchange Rate Risk, Political Environment and Chinese Outward FDI in Emerging Economies： A Panel Data Analysis

This study attempts to investigate the effect of financial and political risk on Chinese outward FDI activities in 56 emerging economies for a period from 2003 to 2013. Exchange rate is taken as a main indicator of financial risks and political risks are evaluated using ICRG （International Country Risk Guide） index. Generalized method of moments with panel data of Chinese outward FDI （foreign direct investment） in new emerging economies is used to find how Chinese finns intend to invest abroad with respect to exchange rate level, volatility, and expectation. The major findings show that RMB appreciation proved to have a positive effect on Chinese outward FDI in emerging economies. But Chinese OFDI （outward foreign direct investment） seems not to respond to exchange rate volatility. The expectation of RMB＇s appreciation has positive effect on Chinese OFDI in emerging economies. Results also show that more political risk leads to more Chinese OFDI in emerging economies.

Study on models for control of interest rate risks

Analyses different interest rate risks, presents a new model for assessment of interest rates and thereby establishes the framework for control of interest

Risk factors for anastomotic fistula development after radical colon cancer surgery and their impact on prognosis

BACKGROUND Colon cancer is a common malignant tumor in the gastrointestinal tract that is typically treated surgically.However,postradical surgery is prone to complic-ations such as anastomotic fistulas.AIM To investigate the risk factors for postoperative anastomotic fistulas and their impact on the prognosis of patients with colon cancer.METHODS We conducted a retrospective analysis of 488 patients with colon cancer who underwent radical surgery.This study was performed between April 2016 and April 2019 at a tertiary hospital in Wuxi,Jiangsu Province,China.A t-test was used to compare laboratory indicators between patients with and those without postoperative anastomotic fistulas.Multiple logistic regression analysis was performed to identify independent risk factors for postoperative anastomotic fistulas.The Functional Assessment of Cancer Therapy-Colorectal Cancer was also used to assess postoperative recovery.RESULTS Binary logistic regression analysis revealed that age[odds ratio(OR)=1.043,P=0.015],tumor,node,metastasis stage(OR=2.337,P=0.041),and surgical procedure were independent risk factors for postoperative anastomotic fistulas.Multiple linear regression analysis showed that the development of postoperative anastomotic fistula(P=0.000),advanced age(P=0.003),and the presence of diabetes mellitus(P=0.015),among other factors,independently affected CONCLUSION Postoperative anastomotic fistulas significantly affect prognosis and survival rates.Therefore,focusing on the clinical characteristics and risk factors and immediately implementing individualized preventive measures are important to minimize their occurrence.

Organ at Risk Doses during High Dose Rate Intracavitary Brachytherapy for Cervical Cancer: A Dosimetric Study

Background: Treatment of Cervical cancer includes a combination of external beam radiotherapy (EBRT) with intracavitary brachytherapy (ICBT). ICBT helps to boost radiation dose to primary disease. Organs like rectum, bladder, sigmoid and small bowel lie close to the cervix region and these organs receive dose from EBRT as well as ICBT and we want to know the dose to these organ at risk (OAR). Materials & Methods: Dosimetric details of 174 ICBT applications done in 58 patients were retrospectively analysed. All patients received EBRT dose of 50.4 Gy in 28 fractions. All patients had ICBT, three sessions with 7 Gy prescribed to point A. Dosimetric data including dose to right and left point A and dose to OARs were recorded from Oncentra Planning System. Results: Mean dose to point A on right side was 6.89 Gy and left side was 6.91 Gy. Mean D2cc dose to rectum, bladder, sigmoid and small bowel was 3.5 Gy, 5.25 Gy, 4.75 Gy and 4.2 Gy respectively. Mean EQD2 dose combining EBRT and ICBT in point A was 78.7 Gy on right side and 79 Gy on left side. Mean EQD2 doses to D2cc of rectum, bladder, sigmoid and small bowel was 62 Gy, 74.4 Gy, 70.5 Gy and 66.5 Gy respectively. Conclusion: From the results of this dosimetric study it is evident that OARs like rectum, sigmoid, bladder & bowel are receiving only acceptable doses of radiation using point A prescribed CT based ICBT planning. Hence with regards to OAR doses, CT based ICBT planning with dose prescribed to point A is a feasible option.

On the Distribution of Duration of First Negative Surplus for a Discrete Time Risk Model with Random Interest Rate

In this paper, we examine further annuity-due risk model presented by Cai （Probability in the Engineering and Informational Sciences, 16（2002）, 309-324）. We consider the computation for the distribution of duration of first negative surplus and the algorithm is shown for calculating probability that ruin occurs and the duration of first negative surplus takes any nonnegative integers values. Numerical illustration for the main result is given.

The Strategies for Market Risk Management in International Shipping

International shipping market is a risky market associated with a variety of risks which shipping companies have to cope with. International shipping has been seriously hit by the financial crisis in 2008. Since then, this industry has experienced market downturn for a long period which was considered to be the longest period of depression in the history. This paper mainly focuses on the key market risks in international shipping including cyclical fluctuation risk, cost risk, freight rate volatility risk, and competition risk. It analyses the source of these market risks, and identifies some strategies to cope with these market risks. In the meantime, Maersk and China Ocean Shipping Group （COSCO）, the world leading international shipping companies, are taken as two cases. Their strategies in market risk management are analyzed, which enable the reader to learn from their success and failure. Based on the international experience in market risk management in shipping industry as well as the real practice of Maersk and COSCO, this paper provides useful guidance for shipping companies to reduce market risks, overcome market downturn, and improve competitiveness.

Managing Interest Rate Risk： An Evaluation of Indian Banks

Interest rate risk represents one of the key forms of financial risk faced by banks. It has given rise to an extensive body of research, .mainly focused on the estimation of sensitivity of bank stock returns to changes in interest rates. However, the analysis of the sources of bank interest rate risk has received much less attention in the literature. It is essential that banks have to monitor, maintain, and manage their assets and liabilities portfolios in a systematic manner taking into account the various risks involved in these areas. Balance sheet risk of a bank can be categorized into two major types of significant risks, which are liquidity risk and interest rate risk （IRR）. IRR is the risk to earning of capital arising from movement of interest rates. The need to manage IRR in Indian banks arises from movement of interest rates. The areas not much considered in the earlier research work are to manage IRR which influences critically the overall profitability of banks. The study was taken with an objective of analyzing the determinants of IRR and examining the strategy to manage such exposures testing the banks long run sustainability. The study had chosen 45 banks and collected secondary data for the financial year 2007 to 2012 to do the analysis of IRR management. The findings of the study were to suggest the ways to minimize the IRR and control its effect on the banks profit. The other findings were to test impact of IRR on the sustainability of the bank.

Exchange Rate Risk of China's Foreign Exchange Reserve Assets--An Empirical Study Based on GARCH-VaR Model

As the core economic variable in the process of the integration of world economy,the change of the exchange rate has an important impact on the import and export,foreign exchange reserves,interest rates,capital flows and other macro and microeconomic factors.This paper first analyzes the status quo of RMB exchange rate risk and the advanced experience of exchange rate management of other countries.Then,the empirical method is used to analyze the characteristics of RMB exchange rate fluctuation based on the day-frequency data of USD/RMB,GBP/RMB,EUR/RMB and JPY/RMB from December 2011 to December 2016.This paper also respectively uses the GARCH,TARCH,EGARCH and PARCH model to fit four representative foreign currencies against RMB,and selects the optimal model to calculate VaR value.Finally,validity of the data is verified through the Chi-square distribution test.The empirical results show that the four sequences are non-normal and first-order monotonic sequences.Besides,there is a significantly high-order ARCH effect,and the GARCH family model has a better fitting effect.JPY/RMB is with lower exchange rate risk,while the fluctuation of EUR/RMB is significantly greater than other currencies.According to the international situation of financial market,the status quo of RMB exchange rate and the conclusion of empirical research,this paper puts forward that the marketization and internationalization of RMB exchange rate should be based on improving the financial system and environment.It is also suggested that the government should properly intervene in the foreign exchange market and make good use of the risk measurement model and commercial banks should further develop the financial derivatives to hedge the foreign exchange risk.

Analysis on Formation Causes of Interest Rate Risks of Commercial Banks in China

Economy globalization inevitably requires financial globalization. The interest rate （IR） is decided by the market, which will bring about IR risks to commercial banks （CBs）. This paper discusses the inevitability of fulfilling market IR in China and what IR risks Chinese CBs have to burden. It also analyzes the formation causes of IR risks from the exterior and the interior aspects.

Risk factors and strategy for surgical incision infection in department of abdominal surgery

Objective To study the risk factors of surgical wound infection among the patients in department of abodominal surgery. Methods The factors on surgical wound infection were investigated by retrospective study. The diagnosis standard was based on Diagnosis Standard of Hospital Infection published by Ministry of Health.

高管团队稳定性与企业ESG评级

ESG评级是推动企业可持续发展的重要动力,是企业长期生存的内在要求,而高管团队在企业长期发展中起着至关重要的作用。基于2010—2019年中国沪深A股上市公司数据,研究了高管团队稳定性对企业ESG评级的影响及其作用机制。研究发现,高管团队稳定性越高,企业ESG评级越高。机制检验显示,高管团队稳定性通过降低企业战略差异度和经营风险提高企业ESG评级。异质性检验结果表明,在内控质量较低、审计质量较低的企业中,高管团队稳定性对企业ESG评级影响效应显著;媒体关注度较低的企业中高管团队稳定性对企业ESG评级的影响更显著。因此,企业要重视高管团队稳定性,采取有效措施降低经营风险,注重ESG信息披露,提升ESG评级,以推动企业可持续发展。

农村成长经历会影响城镇家庭储蓄率吗?——来自CHFS 2019的经验证据

由于城市与农村的经济金融环境存在显著差异,成年前在农村成长的城镇居民比在城市成长的城镇居民具有较高的风险厌恶程度和较低的金融知识水平,从而更加偏向低消费和高储蓄。采用中国家庭金融调查(CHFS)2019年数据,将“目前居住在城市地区且拥有非农业户口、18岁之前为农业户口”作为“拥有农村成长经历”的界定标准,实证检验城镇家庭户主的农村成长经历对其家庭储蓄率的影响,结果表明:户主拥有农村成长经历的城镇家庭比户主没有农村成长经历的城镇家庭有更高的储蓄率,风险态度和金融素养在其中发挥了中介作用,即拥有农村成长经历的户主会因较高的风险厌恶程度和较低的金融知识水平而导致其家庭储蓄率较高;农村成长经历对储蓄率的正向影响在户主受教育水平较高、家庭资产较少、经济发展水平较低地区(中西部地区)的家庭中更为显著。因此,需要从改善城市的经济金融状况(降低生活成本、增强社会保障、减少不确定性等)入手来释放城镇居民的消费需求,并通过改善风险态度、加强金融教育、缩小城乡差距等渠道来降低农村成长经历对城镇家庭储蓄率的正向影响。

基于多源数据的全国三大主粮生产风险评估研究

【目的】“一省、一作物、一费率”的粗放式定价模式带来逆选择、道德风险、经营乱象等问题,严重制约我国农业保险的健康可持续发展。费率定价离不开风险评估,开展全国三大主粮生产风险评估、制作风险地图,为实现我国主粮保险费率精准化、推进主粮保险高质量发展提供依据。【方法】围绕我国三大主粮作物(水稻、小麦、玉米),收集整理长时间序列的三大风险数据源(单产、灾情和保险数据),以单产数据为核心,结合灾情数据和保险数据,开展基于多源数据的风险评估建模,通过县级风险的低估调整和省级风险的秩相关调整,计算全国三大主粮省级和县级的纯风险损失率,采用分位数法开展全国三大主粮风险分区,制作风险地图。【结果】省级风险的秩相关调整以灾情风险结果为主,保险风险结果为次。经调整,水稻秩相关系数由0.610提升到0.766,小麦由0.547提升到0.748,玉米由0.576提升到0.760。调整后,全国三大主粮平均的风险低估系数为20%—40%,说明全国范围内利用县域单产开展风险评估的平均低估程度在2—4成,玉米低估系数要高于水稻和小麦。从省级尺度上看,黑龙江三大主粮生产风险均处于极高水平,内蒙古水稻、小麦,吉林和辽宁水稻、玉米生产风险处于极高水平,山西小麦生产风险处于极高水平;从县级尺度上看,水稻生产的极高风险(纯风险损失率>4.4%)主要集中在东北三省绝大部分种植县域、内蒙古东北部与东北三省接壤的种植县域。小麦生产的极高风险(纯风险损失率>6.3%)主要集中在内蒙古绝大部分种植县域。玉米生产的极高风险(纯风险损失率>6.9%)主要集中在内蒙古与东北三省、山西和陕西接壤的种植县域,辽宁、安徽、江西的大部分种植县域。从全国833个产粮大县上看,玉米极高和高风险县域数量占比最高(28.1%),水稻次之(25.1%),小麦最低(17.2%),说明玉米整体风险水平较高,小麦最低。【结论】研究揭示了我国三大主粮作物生产风险大小与空间差异。从全国平均水平上看,玉米风险最大(平均纯风险损失率为5.0%)、小麦次之(3.1%)、水稻最小(2.6%);从空间差异上看,东北和中南地区水稻风险较高,华北和华东地区小麦风险较高,华北、东北和华东地区玉米风险较高。水稻、小麦和玉米其他级别风险的空间差异特征也不一致。

企业资源配置战略与债券信用评级

企业战略作为企业全局性、长期性资源配置的重要规划,对企业经营活动具有重要影响,也必然会影响企业的融资行为。本文从企业战略视角出发,以2008—2020年中国A股上市公司为研究对象,运用固定效应模型探究了企业资源配置战略对债券信用评级的影响。研究发现:相对于经营主导型企业,投资主导型企业的债券信用评级更低,并且该结论在处理内生性问题和进行一系列稳健性检验后依然成立。异质性分析发现,企业资源配置战略对债券信用评级的影响在非国有企业和分析师跟踪人数多的企业中更明显。中介效应检验结果表明,企业资源配置战略通过作用于企业违约风险而影响债券信用评级。本文的研究结论对发债企业、信用评级机构和债券市场投资者具有重要启示意义。

2型糖尿病合并感染患者肺炎克雷伯菌分布及预后影响因素分析

目的:探讨2型糖尿病(T2DM)合并感染患者肺炎克雷伯菌(KP)分布及预后影响因素分析。方法:选择226例T2DM患者为研究对象,根据是否合并KP感染分为未感染组(n=170)和感染组(n=56),分析T2DM患者感染的危险因素。收集T2DM合并感染患者KP标本,记录标本来源并进行菌种鉴定和药敏试验,并对所有菌株进行多位点序列(MLST)分型,记录预后情况。结果:基础疾病、抗生素使用、侵入性操作、血清白蛋白(ALB)、糖化血红蛋白(HbA1c)、空腹血糖(FPG)为影响T2DM发生感染的危险因素(均P<0.05)。T2DM合并感染患者体内分离56株肺炎克雷伯菌,肺炎克雷伯菌在痰液中的占比最高为44.62%,其次为尿液19.64%,血液中占比16.07%,脓液中占比12.5%,其他标本占比7.14%。56株KP总耐药率最高为氨苄西林,最低为亚胺培南,痰液标本中KP对头孢呋辛、头孢哌酮、庆大霉素耐药率高于非痰液标本,非痰液标本中KP对头孢他啶高于痰液标本(均P<0.05)。56株肺炎克雷伯菌MLST分型共发现42个ST型,ST-20型、36型、65型、347型、660型各2株,分别占3.57%,23型4株占7.14%,ST-17、25、29、35、37、45、86、189、208、211、218、322、355、412、490、519、557、595、726、776、1049、1092、1103、1319、1569、1916、2059、3014、3140、3536、4023、4194、4262、4412、4857型各1株,分别占1.78%,其他ST型7株占比12.5%。56例T2DM合并KP感染患者预后良好患者52例,预后不良患者4例,预后良好率为92.86%。结论:T2DM合并感染患者KP主要分布在痰液和尿液中,基础疾病、抗生素使用、侵入性操作、ALB、HbA1c、FPG是影响KP感染发生危险因素,T2DM合并KP感染患者根据药敏结果选择用药,有利于患者预后。

基于Copula函数的水闸变形实时风险率量化模型

变形监测数据实时反映了水闸结构性态及所受荷载的特性,若能根据水闸变形监测资料确定其失效风险概率,将得到更可靠的结果。将原位监测资料融入水闸失效概率分析中,提出一种基于Copula函数的水闸变形实时风险率量化模型,在考虑水闸各部位监测效应量差异性与关联性的基础上,将单测点变形风险率提升为多测点变形风险率,进而实现水闸整体变形风险率的实时量化分析。实例分析表明,模型实现了水闸变形实测效应量与风险率的动态转化,对水闸变形实时风险率进行了整体分析;所得结果符合水闸整体变形风险率变化的基本规律和客观事实,可有效解读工程监测信息和直观反映工程运行性状,可为水闸工程的运行管理和安全监控提供理论依据与技术支撑。

老年维持性血液透析病人慢性便秘患病率和危险因素研究

目的探讨老年维持性血液透析(maintenance hemodialysis,MHD)病人慢性便秘的患病率及其危险因素。方法选取2023年1—6月东南大学附属中大医院血液净化中心定期随访的116例老年MHD病人为研究对象,收集病人的临床相关指标,采用便秘评分量表(constipation assessment scale,CAS)评估老年MHD病人的便秘水平。采用Pearson相关性分析探讨慢性便秘和临床指标的相关性;使用Logistic回归分析探讨老年MHD病人慢性便秘的危险因素。结果58例(50%)老年MHD病人患有慢性便秘,便秘评分与BMI、TC、TG水平以及总水量(total body water,TBW)、脂肪含量(body fat mass,BFM)和肥胖程度均呈正相关(P<0.05)。二元Logistic回归分析显示,TC、TG、TBW、BFM和肥胖程度是老年MHD病人便秘的危险因素(P<0.05)。结论老年MHD病人便秘的患病率较高,TC、TG、TBW、BFM和肥胖程度对老年MHD病人发生慢性便秘存在显著影响。