珠算除法中易被忽视的问题——除法余数值的认定

珠算除法在珠算教学体系中既是重点又是难点,在长期珠算教学与珠算技术等级鉴定中,笔者发现许多学生对除法题有恐惧感。细细分析,问题多出在有余数除法上。 有余数除法在经济活动中约占90％以上,但在具体处理时,对余数的实际计量单位是多少,往往按精确度采用四舍五入求值,至于多舍了多少,多入了多少?却很少研究,因此很有必要进行分析。

防治颈肩腰腿痛始于青少年

资料表明,80％以上的颈肩腰腿痛诱发因素是长期习惯性的体位不当和姿势不良,包括站、坐、卧以及难以避免的各种非生理性姿势。这些不良姿势的形成往往始于青少年时期。防治劲肩腰腿痛,应始于青少年。 训练良好的动力姿势 良好的姿势就是人体各部位的位置处于能保持各组相拮抗的肌群作用相互平衡,没有过度的伸张或屈曲,各关节、韧带相应稳定,不受过分牵扯。否则就可能发生颈肩腰背部疲劳、不适、疼痛。青少年应从晨起穿衣、刷牙、洗脸、扫地、看电视。

赵堡太极拳推手及点穴

一、推手八法 赵堡太极拳在架式和推手中要取得我顺人背的效果,十分讲究运用十三法和各种劲。 赵堡太极拳十三法的名称与各家太极拳的名称一致,就是:(扌朋)、(扌履)、挤、按、采、(扌列)、肘、靠、进、退、顾、盼、定。

Situation and Development Tendency of Indoor Positioning

This paper introduces the significance of indoor positioning and analyzes the related problems. The latest research on indoor positioning is introduced. Further, the positioning accuracy and the cost of typical local and wide area indoor positioning systems are compared. The results of the comparison show that Time & Code Division-Orthogonal Frequency Division Multiplexing (TC-OFDM) is a system that can achieve real-time meter-accuracy of indoor positioning in a wide area. Finally, in this paper, we indicate that the seamless high-accuracy indoor positioning in a wide area is the development trend of indoor positioning. The seamless Location Based Services (LBS) architecture based on a heterogeneous network, key technologies in indoor positioning for decimeter-accuracy and seamless outdoor and indoor Geographic Information System (GIS) are elaborated as the most important research fields of future indoor positioning.

Privacy-preserving Distributed Location Proof Generating System

The rapid development of location-based service(LBS) drives one special kind of LBS, in which the service provider verifies user location before providing services. In distributed location proof generating schemes, preventing users from colluding with each other to create fake location proofs and protecting user's location privacy at the same time, are the main technical challenges to bring this kind of LBS into practical. Existing solutions tackle these challenges with low collusion-detecting efficiency and defected collusion-detecting method. We proposed two novel location proof generating schemes, which inversely utilized a secure secret-sharing scheme and a pseudonym scheme to settle these shortcomings. Our proposed solution resists and detects user collusion attacks in a more efficient and correct way. Meanwhile, we achieve a higher level of location privacy than that of previous work. The correctness and efficiency of our proposed solution is testified by intensive security analysis, performance analysis, as well as experiments and simulation results.

Pseudo-Location Updating System for Privacy-Preserving Location-Based Services

With the rapid development of location-aware devices such as smart phones,Location-Based Services(LBSs) are becoming increasingly popular. Users can enjoy convenience by sending queries to LBS servers and obtaining service information that is nearby.However, these queries may leak the users' locations and interests to the un-trusted LBS servers, leading to serious privacy concerns. In this paper, we propose a Privacy-Preserving Pseudo-Location Updating System(3PLUS) to achieve k-anonymity for mobile users using LBSs. In 3PLUS, without relying on a third party, each user keeps pseudo-locations obtained from both the history locations and the encountered users, and randomly exchanges one of them with others when encounters occur. As a result, each user's buffer is disordered. A user can obtain any k locations from the buffer to achieve k-anonymity locally. The security analysis shows the security properties and our evaluation results indicate that the user's privacy is significantly improved.

Development of Re-usable C＋＋ classes for Location Aware Management and Control Systems for Shipping Applications

Location aware management and location based automation are fast upcoming technologies which are facilitated by availability of reliable, accurate, and cheap global positioning systems and location based services. This paper discusses the development of C＋＋ classes, which may be used for development of software for location aware management and control, specifically in merchant shipping, so as to provide improved safety, increased automation, prevention of pollution and reducing the work burden of the crew. The GPS is used in conjunction with the regionally accessible nested global shorelines （RANGS） dataset for this purpose. The design of two main C＋＋ classes named CShorelines and CGPSInput have been discussed. A control system mandatory on all oil-tankers above 150 GRT （and few other vessels） called ODMCS has been made location aware using the novel software developed and the results obtained have been critically examined and presented.

回位到哪儿最合适?

当你在边线附近击球后,球在空中飞行的这段时间里,你会做什么呢?是傻傻的呆在原地吗?当然不会,有经验的你一定是迅速地向球场中间移动,以弥补另一侧的大空当,这就叫回位。 回到哪儿是最合适的呢?有人认为从球场的中间到两边的距离是相等的,所以无论打完底线还是网前,都会跑回到球场的中间,即中点、中线的位置,但如果你仔细观察一下职业选手的移动,会发现他们并非如此。职业选手在底线打斜线球后,他们会移动到A点的位置;回直线球后,会移动到B点的位置(图1)。当他们在网前,

场地、球&对手

一位好司机会时刻注意前、侧、后及四周的车辆情况。球员也应该如此,在比赛中要时时刻刻留意对手的一举一动。所以,球员在平常练习时,应训练自己去习惯注意场地、球和对手的情况而达到对这三方面有敏锐的感觉。

预选赛抽签研究

1.引言 乒乓球比赛分为团体赛和单项比赛。单项比赛分为男子单打、男子双打、女子单打、女子双打和混合双打。大型比赛如世乒赛和全国锦标赛的单项比赛一般均采用淘汰赛的竞赛体制。如果竞争赛办法中规定某一个单项比赛的淘汰赛采用某一固定号码位置(如128或64),而这个单项比赛报名人(或对)数超过上述号码位置数时,将在该项目中采用预选赛,使参加该项目正式比赛的选手人(或对)数,符合淘汰赛要求的位置数。至于留多少个经过预选赛的位置,视情况而定。

个性飞扬

几年前到工体看球的时候,想买一张上台第一排的票,但是到了售票处只能买80的、120的、180的票,想指定一下座位的位置,售票员可没有这个功夫伺候你,只能赶上谁是谁。到了后来,连这点选择的余地都没有了——到长城饭店想订几张120的票,被告知没有120元的票,要买到工体售票处去买,于是只好买180的。 而几天前在家里看《足球之夜》,看到德国的球迷可以在很多的地方很方便地买到球票。