Causes,Effects,and Control Measures of Construction Change Orders in the U.S.

Change orders have a significant impact on many aspects of construction projects.They are known to be the primary cause of litigation in the construction industry.Change orders are almost inevitable due to the uniqueness of each project from many perspectives,such as the type of building,complexity of the design,human factors,and the available resources.Change orders are the formal mechanism to implement design changes during the execution phase.These changes are usually the outcome of lack of visualization by the owner,misunderstanding,miscommunication between different parties involved in the project,shortage in resources,and other factors.This research aims to investigate and rank causes,effects,and control measures of change orders in the construction industry in the U.S.This research presents the results of a questionnaire surveying owners,contractors,and consultants.A total of 123 industry professionals in the Architecture,Engineering,and Construction(AEC)field,with either significant or final decision-making authority on reviewing,issuing,and approving change orders responded to the survey.Results indicated that owners are the primary source followed by consultants and contractors,respectively.Some of the more important control measures identified in this research are collaboration and visualization technologies.

Existence of Monotone Positive Solution for a Fourth-Order Three-Point BVP with Sign-Changing Green’s Function

This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones and iterative technique.

TD-SCDMA/GSM/GPRS双模终端CELL CHANGE ORDER过程研究

随着TD-SCDMA系统的商用,同时需兼容已非常成熟运营的GSM系统,TD-SCDMA/GSM/GPRS双模终端已是市场的主流。本文针对双模单待终端(协议控制)CELL CHANGE ORDER过程进行研究,该过程是双模终端实现PS域切换的一种重要方式。首先,以TD-SCDMA/GSM/GPRS系统高层协议为基础介绍了双模单待自动切换终端的CELL CHANGE ORDER过程的各个阶段:系统间测量、网络判决及小区改变执行;然后详细地设计了小区改变执行的正常及异常处理流程,并对如何实现数据平面切换过程进行了重点描述;最后搭建板级测试环境,进行协议一致性测试,验证了CELL CHANGE ORDER过程的实现。

Causes of Change Orders in the Jordanian Construction Industry

Change orders are common and clearly noticeable in Jordanian construction industry. Several studies have identified change orders as significant problem in Jordanian construction projects, and they mainly cause delay and cost overrun. This situation spurs the researchers for investigating the significant causes of change orders in construction projects. Thus, this paper aims to determine the main causes of change orders in the Jordanian construction private sector which responsible for significant cost overrun. Both qualitative and quantitative methods, i.e. interview and questionnaire techniques, were used to achieve this aim. Interviews were conducted as the first stage of data collection, and the results formed the basis of the questionnaire, which was distributed across the Jordanian construction sector. Content analysis was used to analyse the interview responses, while factor analysis, correlation and the Severity Index (SI) were used to analyse the questionnaire results. The findings identified three main categories of causes of change orders in private sector, namely engineering causes, causes related to the client, and circumstances of the project, with sub-causes in each category which are related to each other in significant ways and which affect each other.

Effects. of Change Orders through Technical Programs on Construction Projects in Jordan

Regarding construction projects, no project is implemented exactly as planned. Changes in construction projects are common due to the dynamic nature of the construction process. It is necessary to use effective and appropriate tools by project management to support decision-making and control changes during all stages of project implementation. This study examined the effects of change orders through technical programs on construction projects in Jordan and focused on how to overcome these effects by making usual orders that can be handled by each of the contracting parties. Also, this study added an advantage by not addressing the negative effects of change orders, but it provided many positive effects of change orders by using technical programs method, which has not been yet researched in Jordanian studies in particular, and in global studies in general. The researcher used descriptive analytical method by interviews to collect data through nine questions to a random sample of 30 engineers selected form constructions projects in Jordan. The results related to the study questions on the effect of change orders through technical programs on construction projects in Jordan showed that, most of the study samples confirm that change orders through technical programs decrease the cost of the projects, cause no need for more materials, cause no delay in the completion schedule, enhances the quality of work, and increase the productivity of the work force. The study recommended applying integrated change management system with technical supports form different technologies, developing effective innovative and practical solution to manage change orders and increase training programs to qualify and increase engineering skills in dealing with ICT （information and communication technologies） program.

The Complicated Security Dilemma and Armament Trends in the Middle East: The Order and Change Predicaments

The security dilemma is a common problem faced with the states in the ongoing anarchic international system.It does matter in the Middle East like the other ones and also has its impact on the arms races in the region too.Meanwhile there are some characters named as the order and change predicaments such as the colonial background,weak infrastructure of state construction,and the identity politics embedded in the region that do convert the current complex security dilemma into a complicated one.Not only does it have effect on the regional order,the arm race and disarmament,and also offense/defense paradox,but also does it get on the violent bandwagon in the region.Synergies of the both dilemmas did lead the region into the domestic environment change alongside of regional disorder too.Non-neutral involving the trans-regional powers into the(in)security situation in the region not only did not mitigate the situation but also volatile it too.In conclusion the paper does strive to introduce three phrased manners for transition of the complicated security dilemma.

Analysis of vulnerability and resilience to climate change induced shocks in North Shewa, Ethiopia

This article analyzes the vulnerability and resilience levels of farm households in North Shewa, Ethiopia, using a survey of 452 households. Agro ecological based classification was done to analyze vulnerability to climate change induced shocks. Integrated vulnerability analysis approach was employed to develop indexes for socioeconomic and biophysical indicators. The indicators have been classified into adaptive capacity, exposure and sensitivity to climate change impact. Then Principal Component Analysis was used to compute vulnerability index of each agro ecological zone. The result shows that farmers living in the highland areas were very much vulnerable to natural shocks compared to those living in the lowland area. In order to identify and analyse the determinants of resilience to climate change impacts, ordered probit model was used. Households were classified into three categories based on the time they take to bounce back after natural shocks. The model outputs indicate that farmers with better investment on natural resource management, access to market, better social network, access to credit, preparedness, saving liquid assets, access to irrigation and better level of education exhibited greater level of resilience during and after climate change induced shocks.

Adoption Practice of Climate Change Adaptation Options among Nepalese Rice Farmers: Role of Information and Communication Technologies (ICTs)

This study attempts to understand the role of ICTs on adoption of climate change adaption options among the Nepalese rice farmers, using data from 773 households from seven districts—3 from Terai region and 4 from hilly region. Individual Farmer’s Awareness Index was developed to categorize the respondent knowledge of climate change adaptation and Ordered Logit Model was used to examine the factors influencing their adaptation options in present of ICTs. The result revealed that 65% farmers perceived knowledge about temperature, rainfall and other relative information from various ICT devices that they pose. Farmers received such information mostly from Radio (71%), TV (69%) and mobile phone (62.5%) and argued these three devices are the most prominent, easy access and practical devices to receive such information. 86% farmers used such devices on the daily basis and 90% and more users opined that the information provided from such devices is in their own language and fully understandable. From ICT devices they pose, 71% of the farmers are receiving climate change information and 61% received agro-related information and the majority of them argued that such available information is very much informative and supportive of their resilience to climate change and use of available adaptation options. From the Farmers Awareness Index, this study found 19.8% farmers are high aware, 65.1% medium aware and 15.1% were less aware of the changing climate and its anomalies. Similarly, result from Ordered Logit Model shows that age (0.45***), gender (0.48**), market center (0.32*), bank access (0.54***), availability of subsidy (1.0***), agro-extension services (0.71**), access to TV (0.67***) and membership to a social network (3.20**) played a significant role in increasing farmers’ awareness of climate change which in turn lead to increased adoption of adaptation options available to the farmers. The findings suggest the need for further improvement on ICT devices and publicity of such ICT devices and proper investment to boost rice farmers’ adaptation to climate change, which will in turn help to improve their livelihoods and well-being.

Pros and cons of climate change in China

Climate change strongly affected the structure and functions of natural ecosystems,e.g.the vegetation productivity decreased in the Northeast permafrost region due to the higher temperature and less precipitation,whereas in the Tibetan Plateau,the vegetation productivity increased,owing to the improved thermal resource.Climate change led to reduced precipitation in North and Northeast China and thus the reduced surface runoff.The public needs for energy were changed because of climate change,e.g.the shorter heating period in winter.Climate change profoundly influenced human health,pathophoresis and major projects by increasing extreme events,including frequency and magnitude,and causing more serious water shortage.Under the background of climate change,although the improved thermal resources can be helpful for extending the crop growth period,more extreme events may resulted in more instability in agricultural productivity.Not only did climate change indirectly affect the secondary and tertiary industries through the impacts on agriculture and natural resources,but also climate change mitigation measures,such as carbon tax,tariff and trading,had extensive and profound influences on the socioeconomic system.Further analysis indicated that the impact of climate change presented significant regional differences.The impact had its pros and cons,while the advantages outweighed the disadvantages.Based on the above analysis on the impacts of climate change,we put forward suggestions on coping with climate change.First,scientifically dealing with climate change will need to seek advantages while avoiding the disadvantages of climate change in order to achieve the orderly adaptation to climate change,which is characterized with"Overall best,long-term benefit."Second,quantitative adaptation should be given more attention,e.g.proposing operational schemes and predictable goals and using uncertainty analysis on adaptation measures.Third,more active coping strategy should be adopted to enhance China's future comprehensive competitiveness.The strategies include but are not limited to gradually adjusting the industrial structure,intensifying the research and development(R&D)of emission reduction technology and actively responding to the influence of carbon tax,tariff and trading on socioeconomic development in China.

The COVID-19 Pandemic and Changes Unseen in a Century

The COVID-19 pandemic can be compared to a world war that makes the existing international order unsustainable.The pandemic is interacting with global changes unseen in a century and exerting major impacts on international politics,world economy,major-country relations,the geostrategic landscape,global governance,and development models.In the next three to five years,the international landscape will be a chaotic situation,highlighting not poles but competing states and transformation,thus making it more difficult for major countries to cooperate while medium-sized and small states have to huddle for warmth and seek a way out within their respective regions.Although further observation is required during the ongoing pandemic and worldwide economic recession,some major trends in the world have emerged.A restart to China's international relations is called for.

A Changing World Order

2013 is an important year for South Africa. The country will host the Fifth BRICS Summit in March and also celebrates the 15th anniversary of the establish- ment of diplomatic relations with China. On January 31, Bheki Langa, South African Ambassador to China, sat down with ChinAffica Assistant Executive Editor Tang Qinghua and shared his thoughts on the upcoming BRICS Summit and relations between China and South Africa, An edited version of his opinions follows：

Magnetic Field Induced Entropy Change for La-Fe Based NaZn_(13)-Typed Compounds

Magnetic field induced entropy change was investigated for La-Fe based NaZn13-type compounds with magnetic first-order phase transition. In view of magnetic refrigeration at room temperature, the developing of the materials and the understanding of the entropy change were., reviewed. For La-Fe-Si compounds, the entropy change about 29 J·kg^- 1·K^-1 was obtained at 190 K under the magnetic field of 5 T.While a large entropy change of about 15 J·kg^-1·K^-1 near room temperature under 5 T can be obtained by the substitution of Co for Fe in the compounds. It is found that the entropy change is mainly composed of that contributed from magnetic ordering and crystal lattice. The large entropy change consumed by lattice contribution is mainly due to the magnetic ordering one.

CBL、LBL教学顺序改变对中医内科实践教学的影响

目的研究以案例为基础的教学(CBL)、以授课为基础的教学(LBL)顺序改变,对中医内科实践教学效果的影响。方法选取上海中医药大学附属上海市中西医结合临床医学院中医内科实践学习本科生50名,随机分为观察组和对照组,各25名。对照组运用传统的LBL临床教学方法;观察组运用CBL、LBL教学顺序改变的方法,比较2组教学效果。结果观察组的理论考试、临床技能操作成绩均高于对照组(P<0.05)。学生教学方法满意度方面,是否增强学习兴趣、是否培养科学的推理能力、是否加强分析解决问题的能力、是否增强对知识的理解与掌握、是否有助于基础联系临床和是否引导发散思维6点比较,观察组明显高于对照组(P<0.01)。教师的反馈方面,对于学习的兴趣、是否具有科学的推理能力、能否加强分析解决问题的能力、是否增强对知识的理解与掌握、是否有助于基础联系临床、是否引导发散思维6点比较,观察组明显高于对照组(P<0.01)。结论中医内科实践教学中,应用CBL、LBL教学顺序改变的方法,能增强学生的学习主动性,提高教学成绩,更有助于培养其临床思维,提高学生教学满意度及教师教学质量。

主体性视角下农民集中居住区文化秩序重建的实践逻辑

习近平文化思想是推进建设中华民族现代文明的行动指南,为新时期全面推进乡村文化振兴提供了根本遵循。农村社区是新时期深入实施文化强国战略的实践抓手和重要阵地。农民集中居住区文化秩序变迁属于政府主导的规划型变迁,村庄集聚提升和农民集中居住导致文化空间“脱嵌”,传统村落文化模式及其再生产机制难以为继;生活方式市民化转型引发多元化、个性化文化诉求,与供给侧“文化输血”单一模式形成结构性矛盾;长期处于文化供需结构失衡将诱发社区文化主体性阙如并导致文化秩序重建困境。采用文化主体性理论视角,构建“空间-主体-要素-机制”四位一体分析框架,并基于J省N市的实证经验,阐释农民集中居住区文化秩序重建的实践逻辑。新时期深入实施文化强国和文化振兴战略进程中,农民集中居住区文化秩序主体性重建,一方面,要聚焦“农转居”后不同文化主体的多元化诉求,有效激活红色文化、乡贤文化、孝道文化、睦邻文化等内生要素禀赋,尤其要充分挖掘传统优秀文化要素和红色文化资源的多元价值;另一方面,要创新市场化、社会化、自治化等机制协同重建模式,实现经济回报、精神褒奖、情感慰藉、价值追求等多重文化秩序重建效用最优化。

习近平法治思想中的“大变局”应对方略论

“大变局”应对方略是习近平法治思想立足于“百年未有之大变局”的科学论断,针对积极应对世界大变局的现实需要所彰显之实效导向型共识。其作为一种凸显执行性遵守之行动整合的共同准则与依据,往往围绕建立健全涉外法治体系和营造国际法治新秩序这两种应对方略而具体展开。法治体系应对方略主要表征为建立健全涉外法治体系的原则表达、目标设定与核心要素,法治秩序应对方略则主要表征为营造国际法治新秩序的目标设定、方案要义与路径导向。基于此,全面梳理习近平法治思想中的“大变局”应对方略样态,能够为涉外法治工作的有效推动提供系统的类型化指引。

新制度主义政治学的发展源流、主要议题与前沿探索

新制度主义政治学将制度作为政治分析的基本单元,在与旧制度主义、行为主义研究路径对话的基础上拓宽政治科学的研究视野,为理解政治现象提供中观层次的分析工具和研究方法。新制度主义政治学阐明制度在政治生活中的特定作用,探讨制度在多大程度上发挥独立和持续的影响,推进政治制度的概念化与理论化。制度通过认同与适应机制,构造政治行动者的行为选择框架,使行动者在特定制度条件下具有展开适宜行动的动机和能力。新制度主义政治学从主体能动性与制度变迁的关系、断续性变迁与渐进性变迁的界限、历史经验与全新规则的抉择等方面,理解制度的变迁方式,并关注不同制度领域的制度分化及相互竞争的原则规范如何导致制度框架的冲突,揭示制度更替的动力机制。从理论完善和方法更新的角度来看,新制度主义政治学是对政治科学其他研究路径的补充而非完全替代。

应对显著变化的动态社区检测方法

现实中的网络总是不断变化,网络形态和连接关系也在随着时间推移而不断演变,在动态网络中发现社区的变化一直是个重要课题。当这种变化较为显著时,将导致社区检测算法难以有效利用前一个网络快照中有价值的信息,从而导致下一个时间步的负迁移。为解决算法无法较好适应网络突变问题,提出了一个基于遗传进化思想和高阶知识转移策略的动态社区检测算法。首先利用相邻快照的邻接矩阵相似度确定使用一阶或高阶信息,然后利用蛛网模型进行种群初始化,再通过非支配排序遗传算法NSGA-Ⅱ迭代出位于Pareto前沿的多目标最优解,并设计了新的基因交叉方式以提高种群多样性。最后通过在多个真实数据集及模拟数据集上的实验结果表明,与现有算法相比,该算法在发生网络剧变时能获得时间平滑性更高的社区检测结果,同时也能保持良好的社区模块化程度。

家庭代际关系变迁与农村女儿养老的生成

女儿养老逐渐成为农村家庭应对人口老龄化的重要选择。基于实地调研发现,当前农村已经出现外嫁女参与养老的现象,经济交换的密集性、情感沟通的密切性与代际互动的情境性是导致这一现象的实践逻辑。这背后的根源在于农村家庭代际关系的转型,从传统的伦理型代际关系转变为现代的实践型代际关系,而实践型代际关系也为女儿养老提供了契机,重塑了农村家庭对女儿的角色期待,形塑了女儿与娘家互动的新样态。由此,中国农村家庭在现代化转型过程中形成了儿女共同参与养老的“双系养老”新秩序,而家庭代际关系变迁的视角也为理解中国农村家庭养老秩序提供了新的解释路径。

制度变迁与城乡居民的流动感知

流动感知是民众对自身社会地位变动的主观感受,是理解社会心态的重要视角。本研究建立了理解流动感知的理论框架,在城乡资源配置制度和户籍制度变迁的背景下论述了流动感知的形成机制,然后基于2010—2021年七期中国综合社会调查(CGSS)的数据分析发现:首先,流动感知的分布向上偏移,大部分居民都有积极的流动感知;其次,流动感知在农村居民、流动人口、户籍移民和城市土著居民四类群体中存在显著差异,农村居民的流动感知最积极,城市土著居民的流动感知最消极;最后,流动感知的城乡差异存在世代效应,年长世代流动感知的城乡差异比年轻世代更明显。本研究从整体视角分析城乡居民的流动感知,为理解制度变迁与社会心态的复杂关系提供了启示。

基于北斗的超长距离跨河高程测量技术研究与实践

目前常用的跨河高程测量方法有水准测量、测距三角高程测量、GNSS测量。常规水准测量视距较短,测距三角高程测量对场地条件要求非常高,要求测点间相互通视并同步对向观测,测量精度受风力、大气折光、距离远近影响较大,随着测量距离的增加,垂线偏差的影响也随之增大,导致精度降低。当跨距超过3500 m时,没有相关标准规范可以遵循,对于跨度10 km以上的超长距离跨河高程传递测量,更是一个较大的挑战。本文研究对超长距离跨江工程进行高程测量的方法。首先介绍基于北斗跨河水准测量方法的基本原理;然后以沪渝蓉高铁崇太过江隧道跨长江高程传递为例,阐述在跨河水准测量实施过程中水准控制网的布设方法、外业测量质量控制、数据处理及精度分析等。实践结果表明,在地势较平坦、高程异常变化率相对平缓的测区,通过布设强制观测墩、优化设计控制网网形、采用双测线跨河水准测量方法,内外符合精度指标均可满足二等水准测量要求。本文成功实现了10.2 km超长距离跨河水准测量技术在沪渝蓉高铁崇太过江隧道二等水准传递应用,对类似工程项目有很好的借鉴和参考意义。