A Trajectory Privacy Protection Method to Resist Long-Term Observation Attacks

Users face the threat of trajectory privacy leakage when using location-based service applications, especially when their behavior is collected and stored for a long period of time. This accumulated information is exploited by opponents, greatly increasing the risk of trajectory privacy leakage. This attack method is called a long-term observation attack. On the premise of ensuring lower time overhead and higher cache contribution rate, the existing methods cannot utilize cache to answer subsequent queries while also resisting long-term observation attacks. So this article proposes a trajectory privacy protection method to resist long-term observation attacks. This method combines caching technology and improves the existing differential privacy mechanism, while incorporating randomization factors that are difficult for attackers to recognize after long-term observation to enhance privacy. Search for locations in the cache of both the mobile client and edge server that can replace the user’s actual location. If there are replacement users in the cache, the query results can be obtained more quickly. Simultaneously obfuscating the spatiotemporal correlation of actual trajectories by generating confusion regions. If it does not exist, the obfuscated location generation method that resists long-term observation attacks is executed to generate the real anonymous area and send it to the service provider. The above steps can comprehensively protect the user’s trajectory privacy. The experimental results show that this method can protect user trajectories from long-term observation attacks while ensuring low time overhead and a high cache contribution rate.

Long-Term Geophysical Observations and Analysis of the World's Deepest Borehole

Objective In order to reduce the interfering noise from the earth surface, scientists have carried out multi-geophysical borehole observations and the related study. This study aims at improving signal-to-noise ratio obtained from the observation data to obtain zero noise data, which will be of great help to improve geophysical studies. Insights from this study will be significant for the earthquake disaster reduction, resource exploration and environmental protection.

Dynamics of Bottom Boundary Layers in the Yellow River Subaqueous Delta Based on Long-Term In-Situ Observations

Objective In geo-marine science,the generalized bottom boundary layer（BBL）represents a layer between sediments and seawater.The BBL plays an important role in geological,geobiochemical,geophysical and geotechnical research because it is the connection region of hydrosphere,

Observation of Atomic Dynamic Behaviors in the Evaporative Cooling by In-Situ Imaging the Plugged Hole of Ultracold Atoms

We experimentally observe the dynamic evolution of atoms in the evaporative cooling, by in-situ imaging the plugged hole of ultracold atoms. Ultracold rubidium atoms confined in a magnetic trap are plugged using a blue-detuned laser beam with a waist of 20 m at a wavelength of 767 nm. We probe the variation of the atomic temperature and width versus the radio frequency in the evaporative cooling. Both the behaviors are in good agreement with the calculation of the trapping potential dressed by the rf signal above the threshold temperature,while deviating from the calculation near the phase transition. To accurately obtain the atomic width, we use the plugged hole as the reference to optimize the optical imaging system by precisely minimizing the artificial structures due to the defocus effect.

Ocean current observation and spectrum analysis in central Chukchi Sea during the summer of 2008

During the summer of 2008, the third CHINARE Arctic Expedition was carried out on board of Xuelong Icebreaker in the central Chukchi Sea. A submersible mooring system was deployed and recovered at Station CN-01 （71.40.024＇N, 167.58.910＇W） with 33 days of the current profile records, and continuous observation of temperature and salinity data were collected. This mooring station locates in the blank of similar observation area and it is the first time for our Chinese to finish this kind of long-term mooring work in this area. This mooring system finished integrated hydrological observations with long-term continuous record of the whole profile velocity for the first time. Based on time series analysis of temperature, salinity, velocity and flow direction, we get the following main results. （1） During the observation period, the mean surface current velocity is 70.2 cm/s eastward, and velocity reaches its maximum in average at 3 m level with magnitude 90.0 cm/s, direction 206.. （2） In 9-30 m layers, the semidiurnal period variation is the most obvious, the flow direction is quite stable, and the flow is synchronous and consistent vertically. （3） Besides the semidiurnal period variation, the main variation in the upper layer is in 11-d period, with variations in period 5.5, 5.5, and 3.7 d, which reflect the influences of sea surface wind change and maintenance. （4） Near the bottom the temperature change is correlated and synchronized with the conductivity.

Predictors of Discontinuation of Antipsychotic Therapy in Patients with Acute Schizophrenia: A 1-Year Observational Study with More Than 1000 Patients

Discontinuation of antipsychotic therapy has been a significant clinical issue among patients with schizophrenia, since the patients who discontinued antipsychotic treatment showed worse clinical and functional outcomes, and higher risks of relapse of schizophrenia symptoms and hospitalization. We conducted a post-hoc analysis of a post-marketing research with a 12-month follow-up period to identify the predictors for discontinuation of antipsychotic monotherapy in Japan. This is a prospective, naturalistic multicenter observational study, designed to evaluate the discontinuation rates of olanzapine monotherapy and non-olanzapine antipsychotic monotherapy in Japanese adult patients with acute schizophrenia. Patients were treatment-naive, or had switched from other antipsychotics or from poly-pharmacotherapy to oral antipsychotic monotherapy. We analyzed the correlation of discontinuation of antipsychotic monotherapy with baseline characteristics of patients. A total of 1089 patients (578 patients treated with olanzapine and 511 with non-olanzapine antipsychotics) were eligible for analysis. By the end of the 12-month study period, 614 patients (56.4%) discontinued antipsychotic therapy. Multivariate logistic regression analyses indicated significantly lower discontinuation rates in all patients treated with antipsychotics: older age (Odds ratio [OR], 0.871;95% confidence interval [CI], 0.797 to 0.953;p = 0.003), outpatient status (OR, 0.508;95% CI, 0.383 to 0.675;p < 0.001), prior use of antipsychotics (OR, 0.693;95% CI, 0.516 to 0.930;p = 0.015), and olanzapine group showed lower discontinuation rate than that of non-olanzapine group (OR, 1.416;95% CI, 1.086 to 1.846;p = 0.010). The present study indicated that the outpatient status, older age, and prior use of antipsychotics have better adherence to antipsychotic treatment. In addition to these factors, use of anti-parkinson agents showed lower discontinuation rates in the olanzapine monotherapy group.

Covariability of Subantarctic Mode Water and the Southern Branch of the Subtropical Indian Ocean Countercurrent in Argo Observations

The Subantarctic Mode Water(SAMW)forms in the deep mixed layer north of the Antarctic Circumpolar Current and spreads northward into the subtropical gyre.The subtropical South Indian Countercurrent(SICC)flows eastward on the north flank of the thick SAMW layer within 22°-32°S from south of Madagascar at around 25°S,50°E toward western Australia.The dynamical relation of the SAMW and the southern branch of the SICC(30°-32°S)is investigated in this work based on the monthly mean Argo data from 2004 to 2019.The physical properties of the SAMW and its pathway from the formation region are described.Most of the SAMW in the Indian Ocean sector originates from the deep mixed layers of the southeastern Indian Ocean(about 40°S,85°-105°E)and moves along the subtropical gyre.It takes around ten years to arrive east of Madagascar Island preserving its low potential vor-ticity characteristics.As a thick layer with homogeneous vertical properties,the SAMW forces the upper pycnocline to shoal,and the associated eastward shear results in the surface-intensified SICC.The SAMW forms a tongue-shaped thickness pattern,which influ-ences the southern branch of the SICC above the northern flank of the thickest SAMW layer between 24°S and 32°S.The seasonal,interannual,and decade variations of the southern branch of the SICC are closely related to the meridional gradient of the underlying SAMW thickness.The SAMW thickened and strengthened from 2005 to 2015,thereby anchoring a strengthened SICC.The interan-nual covariability of the SAMW and SICC further supports the SAMW’s role in driving SICC variability.

Oncological results, functional outcomes and health-related quality-of-life in men who received a radical prostatectomy or external beam radiation therapy for localized prostate cancer： a study on long-term patient outcome with risk stratification

Health-related quality-of-life （HRQOL） after a radical prostatectomy （RP） or extemal beam radiation therapy （EBRT） has not been studied in conjunction with oncological outcomes in relation to disease risk stratification. Moreover, the long-term outcomes of these treatment approaches have not been studied. We retrospectively analyzed oncological outcomes between consecutive patients receiving RP （n = 86） and EBRT （n = 76） for localized prostate cancer. HRQOL and functional outcomes could be assessed in 62 RP （79%） and 54 EBRT （79%） patients over a 3-year follow-up period （median： 41 months） using the Medical Outcomes Study Short Form-36 （SF-36） and the University of Califomia Los Angeles Prostate Cancer Index （UCLA PCI）. The 5-year biochemical progression-free survival did not differ between the RP and EBRT groups for low-risk （74.6% vs. 75.0%, P = 0.931） and intermediate-risk （61.3% vs. 71.1%, P = 0.691） patients. For high-risk patients, progression-free survival was lower in the RP group （45.1%） than in the EBRT group （79.7%） （P = 0.002）. The general HRQOL was comparable between the two groups. Regarding functional outcomes, the RP group reported lower scores on urinary function and less urinary bother and sexual bother than the EBRT group （P 〈 0.001, P 〈 0.05 and P 〈 0.001, respectively）. With risk stratification, the low- and intermediate-risk patients in the RP group reported poorer urinary function than patients in the EBRT group （P 〈 0.001 for each）. The sexual function of the high-risk patients in the EBRT group was better than that of the same risk RP patients （P 〈 0.001）. Biochemical recurrence was not associated with the UCLA PCI score in either group. In conclusion, low- to intermediate-risk patients treated with an RP may report relatively decreased urinary function during long-term follow-up. The patient＇s HRQOL after treatment did not depend on biochemical recurrence.

Comparative study on discharge conditions in micro-hole electrical discharge machining of tungsten carbide (WC-Co) material

WC-Co is used widely in die and mold industries due to its unique combination of hardness, strength and wear-resistance. For machining difficult-to-cut materials, such as tungsten carbide, micro-electrical discharge machining(EDM) is one of the most effective methods for making holes because the hardness is not a dominant parameter in EDM. This paper describes the characteristics of the discharge conditions for micro-hole EDM of tungsten carbide with a WC grain size of 0.5 μm and Co content of 12%. The EDM process was conducted by varying the condenser and resistance values. A R-C discharge EDM device using arc erosion for micro-hole machining was suggested. Furthermore, the characteristics of the developed micro-EDM were analyzed in terms of the electro-optical observation using an oscilloscope and field emission scanning electron microscope.

Thermodynamic geometry of the RN-Ad S black hole and non-local observables

This paper studies the thermodynamic geometry of the Reissner–Nordstr?m-anti-de Sitter(RN-AdS)black hole via detection of the non-local observables in the dual field theory,including the entanglement entropy and equal-time two-point correlation function.With the dimensional analysis,we construct the principle of corresponding states of black hole thermodynamics.As a result,our findings can be applied to black holes with different Ad S backgrounds.In this sense,the probe of the thermodynamic geometry of the RN-Ad S black hole though the non-local observables in dual field theory has been confirmed numerically.

担水沟煤矿特厚煤层开采底板导水破坏带深度实测研究

为了研究特厚煤层开采对工作面底板破坏深度的影响,通过在担水沟煤矿9204工作面底板2个观测钻孔,运用直流电法观测分析工作面回采过程中底板岩体视电阻率的变化特征,结合工作面与测点的空间位置关系,得出采动影响下的底板破坏深度,并将其与未考虑煤厚因素影响的统计公式和理论公式的计算值进行比较分析。结果表明,工作面实测底板破坏深度为17.3 m和18.3 m;实测底板最大破坏深度小于统计公式值7.81%~12.90%,大于理论公式值24.81%。探讨其机理认为,相对于工作面斜长、采深等因素,煤厚因素对底板破坏深度影响较低;且工作面底板下17 m赋存有一厚层隔水砂质泥岩,不易产生导水裂缝,降低了底板导水破坏深度。

煤峪口矿首采工作面复杂地质条件“四位一体”综合探测技术研究

为进一步查清首采工作面构造及煤层赋存发育情况,首次采用井下探孔窥视结合测井技术、单巷槽波反射法、井下定向钻探技术、透、反射联合勘探法“四位一体”综合探测技术体系,避免了以往单纯地依靠钻探所造成的工作量极大且预测准确率较低的弊端,同时准确地预测断层及破碎带位置,保障煤矿安全高效生产。

基于马坑铁矿深部开采的地下水动态监测完善方案

为解决马坑铁矿深部开采地下水监测存在检测效果不佳的问题,根据水文观测孔布置原则及涌水量实际监测需要,通过新增7个水文观测孔、5个涌水量观测站,并结合原有水文观测孔,建立了地表与井下联合的地下水自动监测系统,实现了对矿区地下水动态变化的实时监测,为矿区防治水提供可靠预测预报基础。

某车型转向节支架装配孔开裂问题的分析

某车型在路试过程中反馈转向节支架装配孔出现开裂问题。使用电子显微镜和金相显微镜对开裂处进行观察分析,发现疲劳辉纹;利用Altair Hypermesh和Abaqus软件建立CAE装配模型分析转向节支架应力变化;通过ADAMS仿真软件提取螺栓的受力载荷来计算最小抗滑移力;使用超声波轴力测量系统和多功能螺纹紧固件模拟装配测试系统测量夹紧力,试验表明,螺栓夹紧力小于设计最小抗滑移力,导致安装面发生滑移,转向节支架受到螺栓的冲击力而产生疲劳开裂。通过提升螺栓螺母机械性能等级,采用扭矩转角工艺来提高装配夹紧力;最后通过工艺验证和路试验证验证了更改措施是有效的。

孔洞储层地震波特征响应的物理模型实验研究

根据物理模型相似性原则制作了不同材料和不同孔洞密度的物理模型,在常温常压和温压条件下分别测试了孔洞模型的地震波特征响应,分析了孔洞储层特征的变化对地震波属性参数的影响。孔洞密度、围压、温度、模型材料和含流体的变化对地震波的速度、振幅、衰减、主频和主振幅等属性参数均有明显的影响。温压等条件的不同,孔洞密度引起的地震波特征响应程度不同。实验表明,孔洞密度的变化对地震波动力学特征参数(振幅、衰减等)的影响远远大于对运动学特征(速度等)的影响,这为利用地震波的振幅、衰减等属性参数进行储层中孔洞分布和发育程度的检测提供了可靠的实验基础。

硐体应变映震能力综述

搜集整理了我国硐体应变观测二十多年来已发表的观测成果,归纳出常用的硐体应变资料处理方法。通过统计在历次地震发生前震中附近一定范围内硐体应变观测是否出现异常,得到了其异常与震中及震级的统计关系。

某大坝渗漏勘察分析与防渗处理措施

大坝渗漏问题一直是水利工程中的热点和难点问题,渗漏勘察往往需要投入大量的人力、财力和技术。以某大坝渗漏勘察为例,研究了该水库坝址区的地层岩性、地质构造、水文地质、渗漏体系及渗漏概况,并提出了相应的勘察方法及手段。以坝顶钻孔为工作平台,采用地下水位观测、示踪试验、孔内彩电观察、压水试验等勘察手段对大坝渗漏部位进行分析与定位,最终在平面及剖面方向上确定了大坝渗漏范围。根据勘察结果以及渗漏程度对渗漏部位进行分区,并提出了相应处理措施及建议。工程实践表明,所采取的勘察方法和手段是行之有效的,可为类似工程勘察提供参考和借鉴。

面临断流的高温热水井的技术改造及其观测效果

河北省怀4地下流体综合观测井自2007年起水流不断减少,直至濒临断流,我们将其改造成竖井以保证持续进行地下水化学量浓度和水位综合观测。改造后一年多的实践表明,改造是较为成功的,不仅解决了该井停测的危机,还为其他高温热水自流井未来改造开拓了新的技术途径。

覆岩导水裂隙带发育高度分析

为准确测定太平煤矿某工作面开采的导水裂隙带高度、确定工作面合理开采上限,运用"双端堵水器"技术,采用井下打仰上孔的方法,实测了覆岩导水裂隙带的发育高度。观测结果表明,该工作面导水裂缝带发育高度为23.85 m,裂采比为13.2。实测结果与理论预计值和数值模拟值基本吻合,相互得到验证。