Inter-Observer Variability in the Detection and Interpretation of Chest X-Ray Anomalies in Adults in an Endemic Tuberculosis Area

Purpose: To assess the inter-observer agreement in reading adults chest radiographs (CXR) and determine the effectiveness of observers in radiographic diagnosis of pulmonary tuberculosis (PTB) in a tuberculosis endemic area. Methods: A quasi-observational study was conducted in the Pneumology Department of Yaounde Jamot Hospital (Cameroon) from January to March 2014. This included six observers (two chest physicians, two radiologists, two end-training residents in medical imaging) and 47 frontal CXRs (4 of diffuse interstitial lung disease, 6 normal, 7 of lung cancers, 7 of bacterial pneumonia, 23 of PTB). The sample size was calculated on the basis of an expected 0.47 Kappa with a spread of 0.13 (α = 5%, CI = 95%) for six observers and five diagnostic items. The analysis of concordance was focused on the detection of nodules, cavitary lesions, pleural effusion, adenomegaly and diagnosis of PTB and lung cancer. These intervals of kappa coefficient were considered: discordance (0.81). Results: The average score for the detection of caverns was the highest (58.3%) followed by that of the correct diagnosis of tuberculosis (49.3%). Pneumologists had the highest proportions of correct diagnosis of tuberculosis (69.6% and 73.9%) and better inter-observer agreement (k = 0.71) for PTB diagnosis. Observers were more in agreement for the detection of nodules (0.32 - 0.74), adenomegalies (0.43 - 0.69), and for the diagnosis of cancer (0.22 - 1) than for the diagnosis of tuberculosis (0.19 - 0.71). Disagreements were more frequent for the detection of pleural effusions (-0.08 - 0.73). Conclusion: The inter-observer agreement varies with the type of lesions and diagnosis. Pneumologists were most effective for the diagnosis of pulmonary tuberculosis. Observers were more in agreement for the detection of nodules and the diagnosis of cancer than for the diagnosis of pulmonary tuberculosis.

INTER-OBSERVER VARIATIONS OF DIGITAL RADIOGRAPH PULMONARY NODULE MARKING BY USING COMPUTER TOOLKIT

Objective To assess inter-observer variations of pulmonary nodule marking in routine clinical chest digital radiograph (DR) softcopy reading by using a lung nodule computer toolkit.Methods A total of 601 chest posterior-anterior DR images were randomly selected from routine outpatient screening in Peking Union Medical College Hospital. Two chest radiologists with experience more than ten years were first asked to read the images and mark all suspicious nodules independently by using computer toolkit IQQA-Chest, and to indicate the likelihood for each nodule detected. They were also asked to draw the boundary of the identified nodule manually on an enlarged region of interest, which was instantly analyzed by IQQA-Chest. Two sets of diagnostic reports, including the marked nodules, likelihood, manually drawn boundaries, quantitative measurements, and radiologists’ names, were automatically generated and stored by the computer system. One week later, the two radiologists read the same images together by using the same computer toolkit without referring to their previous reading results. Marking procedure was the same except that consensus was reached for each suspicious region. Statistical analysis tools provided in the IQQA-Chest were used to compare all the three sets of reading results.Results In the independent readings, Reader 1 detected 409 nodules with a mean diameter of 12.4 mm in 241 patients, and Reader 2 detected 401 nodules with a mean diameter of 12.6 mm in 253 patients. In the consensus reading, a total of 352 nodules with a mean diameter of 12.4 mm were detected in 220 patients. Totally, 42.3% of Reader 1’s and 45.1% of Reader 2’s marks were confirmed by the consensus reading. About 40% of each reader’s marks agreed with the other. There were only 130 (14.4%) out of the total 904 unique nodules were confirmed by both readers and the consensus reading. Moreover, 5.6% (51/904) of the marked regions were rated identical likelihood in all three readings. Statistical analysis showed significant differences between Readers 1 and 2, and between consensus and Reader 2 in determining the likelihood of the marks (P<0.01), but not between consensus and Reader 1. No significant difference in terms of size was observed in nodule segmentation between either two of the three readings. Conclusion Large variations in nodule marking and nodule-likelihood determination but not in nodule size were observed between experts as well as between single-person reading and consensus reading.

A Technical Note: Inter-Observer and Inter-Modality Variability of Cone-Beam Computed Tomography (CBCT) and Ultrasound (US) in Stereotactic Body Radiotherapy for Kidney Cancer

Introduction: To investigate the inter-observer and inter-modality variabilities of two imaging guided equipments—cone-beam computed tomography (CBCT) and ultrasound (US) in kidney stereotactic body radiotherapy. Methods: A renal metastasis case implanted with three gold anchor fiducial markers was firstly scanned by US to acquire a 3-dimension US image and followed by 4-dimension CBCT in every fraction. Seven observers retrospectively registered the pre-treatment images with the corresponding reference images based on the gold markers. Registration uncertainty of the observers between two imaging modalities was evaluated. Results: The uncertainties over whole treatment course in CBCT were 0.88 mm, 1.94 mm and 0.86 mm in lateral, longitudinal and vertical directions respectively;while 0.8 mm, 0.97 mm and 1.36 mm were found in US. Conclusion: The greatest uncertainty was found in longitudinal direction in CBCT due to the fact that the respiration motion is the most rigorous in cranial-caudal direction. In US, since the probe was hold almost in upright position, the strong echo in vertical direction was attributed to the greatest uncertainty for such direction.

Dosimetric Effects Due to Inter-Observer Variability of Organ Contouring When Utilizing a Knowledge-Based Planning System for Prostate Cancer

Purpose: Radiotherapy is a widely accepted standard of care for early-stage prostate cancer, and it is believed that the plan quality and treatment outcome are associated with contour accuracy of both the target and organs-at-risk (OAR). The purposes of this study are to 1) assess geometric and dosimetric uncertainties due to inter-observer contour variabilities and 2) evaluate the effectiveness of geometric indicators to predict target dosimetry in prostate radiotherapy. Methods: Twenty prostate patients were selected for this retrospective study. Five experienced clinicians created unique structure sets containing prostate, seminal vesicles, bladder, and rectum for each patient. A fully automated script and knowledge-based planning routine were utilized to create standardized and unbiased plans that could be used to evaluate changes in isodose distributions due to inter-observer variability in structure segmentation. Plans were created on a “gold-standard” structure set, as well as on each of the user-defined structure sets. Results: Inter-observer variability of contours during structure segmentation was very low for clearly defined organs such as the bladder but increased for organs without well-defined borders (prostate, seminal vesicles, and rectum). For plans generated with the user-defined structure sets, strong/moderate correlations were observed between the geometric indicators for target structure agreement and target coverage for both low-risk and intermediate-risk patient groups, while OAR indicators showed no correlation to final dosimetry. Conclusions: Target delineation is crucial in order to maintain adequate dosimetric coverage regardless of the associated inter-observer uncertainties in OAR contours that had a limited impact upon final dosimetry.

Inter-Observer Variability in the Interpretation of 68Ga-PSMA PET-CT Scan according to PROMISE Criteria

Aims & Objectives: Aim of the study was to evaluate inter-observer variability in interpretation of Gallium-68 labeled Prostate Specific Membrane Antigen sub-type 11 (68Ga-PSMA-11) Positron Emission Tomography-Computed Tomography PET_CT scan according to Prostate Cancer Molecular Imaging Standardized Evaluation (PROMISE) criteria. Method and Materials: Forty-four consecutive patients of prostate cancer were prospectively studied between the duration of January 2021 to June 2021 at Institute of Nuclear Medicine and Oncology (INMOL), Lahore. All PET-CT scans were assessed by a researcher and 3 nuclear physicians and divided into two groups, interpreted in two phases. In the first phase, each group independently evaluated the scans while in the second phase, a consensus meeting was held and all the cases with discordance were discussed. Cohen’s Kappa test was used to measure interobserver variability with the cut-off of K’s alpha Results: The study showed 41 out of 44 scans with positive PSMA findings while 03 scans were negative for any PSMA avid disease. In the first phase of image analysis, the level of agreement was slight in T stage (Kappa = 0.068, p = 0.65), moderate in the miN stage (Kappa = 0.46, p = 0.02) and substantial in miM stage (Kappa = 0.77, p ≤ 0.001) was seen. For PSMA score, overall agreement was substantial agreement (Kappa = 0.64, p Conclusion: Remarkable inter-observer agreement was seen in PROMISE criteria.

Interrater Reliability Estimation via Maximum Likelihood for Gwet’s Chance Agreement Model

Interrater reliability (IRR) statistics, like Cohen’s kappa, measure agreement between raters beyond what is expected by chance when classifying items into categories. While Cohen’s kappa has been widely used, it has several limitations, prompting development of Gwet’s agreement statistic, an alternative “kappa”statistic which models chance agreement via an “occasional guessing” model. However, we show that Gwet’s formula for estimating the proportion of agreement due to chance is itself biased for intermediate levels of agreement, despite overcoming limitations of Cohen’s kappa at high and low agreement levels. We derive a maximum likelihood estimator for the occasional guessing model that yields an unbiased estimator of the IRR, which we call the maximum likelihood kappa (κML). The key result is that the chance agreement probability under the occasional guessing model is simply equal to the observed rate of disagreement between raters. The κMLstatistic provides a theoretically principled approach to quantifying IRR that addresses limitations of previous κcoefficients. Given the widespread use of IRR measures, having an unbiased estimator is important for reliable inference across domains where rater judgments are analyzed.

Chaotic Map-Based Authentication and Key Agreement Protocol with Low-Latency for Metasystem

With the rapid advancement in exploring perceptual interactions and digital twins,metaverse technology has emerged to transcend the constraints of space-time and reality,facilitating remote AI-based collaboration.In this dynamic metasystem environment,frequent information exchanges necessitate robust security measures,with Authentication and Key Agreement(AKA)serving as the primary line of defense to ensure communication security.However,traditional AKA protocols fall short in meeting the low-latency requirements essential for synchronous interactions within the metaverse.To address this challenge and enable nearly latency-free interactions,a novel low-latency AKA protocol based on chaotic maps is proposed.This protocol not only ensures mutual authentication of entities within the metasystem but also generates secure session keys.The security of these session keys is rigorously validated through formal proofs,formal verification,and informal proofs.When confronted with the Dolev-Yao(DY)threat model,the session keys are formally demonstrated to be secure under the Real-or-Random(ROR)model.The proposed protocol is further validated through simulations conducted using VMware workstation compiled in HLPSL language and C language.The simulation results affirm the protocol’s effectiveness in resisting well-known attacks while achieving the desired low latency for optimal metaverse interactions.

Cautionary Remarks When Testing Agreement between Two Raters for Continuous Scale Measurements: A Tutorial in Clinical Epidemiology with Implementation Using R

Background: When continuous scale measurements are available, agreements between two measuring devices are assessed both graphically and analytically. In clinical investigations, Bland and Altman proposed plotting subject-wise differences between raters against subject-wise averages. In order to scientifically assess agreement, Bartko recommended combining the graphical approach with the statistical analytic procedure suggested by Bradley and Blackwood. The advantage of using this approach is that it enables significance testing and sample size estimation. We noted that the direct use of the results of the regression is misleading and we provide a correction in this regard. Methods: Graphical and linear models are used to assess agreements for continuous scale measurements. We demonstrate that software linear regression results should not be readily used and we provided correct analytic procedures. The degrees of freedom of the F-statistics are incorrectly reported, and we propose methods to overcome this problem by introducing the correct analytic form of the F statistic. Methods for sample size estimation using R-functions are also given. Results: We believe that the tutorial and the R-codes are useful tools for testing and estimating agreement between two rating protocols for continuous scale measurements. The interested reader may use the codes and apply them to their available data when the issue of agreement between two raters is the subject of interest.

基于WS-Agreement的资源预留与QoS监控框架

目前还没有遵循OGSA/WSRF规范的网格服务中间件能够很好地支持基于QoS协商的网格资源管理,因此重点研究了如何设计一个执行服务级协定(SLA)的框架,能够在网格中协商资源预留和任务执行期间对所在资源的QoS监控。首先通过定义资源预留的XML Schema,使得资源请求者和提供者基于WS-Agreement能够协商包含关于资源预留的协定;然后遵循WSRF及WS-*规范设计和开发出一组Web服务用于构建一个基于WS-Agreement的资源预留与QoS监控框架(RMF),并将其集成到Globus资源管理模型中;最后通过理论分析和模拟实验评估了RMF的综合性能。

Possible Chinese Strategic Responses to the Trans-Pacific Partnership Agreement

Negotiations for the Trans-Pacific Partnership （TPP） Agreement have concluded, but the TPP still must be ratified by each of the 12 member countries. China is the world＇s second largest economy and yet it has not joined the TPP. This has provoked much debate in China as to the best strategic approach to the TPP This paper analyzes China＇s possible strategy for the TPP agreement. We make three key points. First, the security of market access should be China＇s main concern in any free-trade agreement negotiations, regrettably, it is not included in TPP. The second point is that the present TPP agreement is somewhat diminished from its ambitious original claims. We suggest four strategies for China. The first is to promote the development of China＇s remaining regional and bilateral free trade agreements （FTAs）. The second is to negotiate a bilateral FTA with the United States. The third is to promote deep domestic reforms via enlarged TPP coverage. The last is negotiating entrance to the entering do not worsen. TPP as soon as possible so that terms of

FORMAL PROOF OF RELATIVE STRENGTH OF SECURITY AMONG ECK2007 MODEL AND OTHER PROOF MODELS FOR KEY AGREEMENT PROTOCOLS

The differences among the extended Canetti ＆ Krawezyk 2007 model （ECK2007） and other four models, i.e., the Bellare ＆ Rogaway （1993, 1995）models （BR93,BR95）, the Bellare, Pointcheval ＆ Rogaway （2000） model （BPR2000） and the Canetti ＆ Krawczyk （2001） model （CK2001） are given. The relative strength of security among these models is analyzed. To support the implication or non-implication relation among these models, the formal proof or the counter-example is provided.

Security agreement汉译探析

security agreement通常译为"担保协议",内容囊括动产担保与不动产担保。但在美国的法律文本中,security agreement的含义范围与中国法律中的"担保合同"并不对等。文章围绕security agreement在美国法律中的不同含义讨论其中文译名。

Two-Party Authenticated Key Agreement in Certificateless Public Key Cryptography

Certificateless public key cryptography was introduced to overcome the key escrow limitation of the identity-based cryptography. It combines the advantages of the identity-based cryptography and the traditional PKI. Many certificateless public key encryption and signature schemes have been proposed. However, the key agreement in CL-PKE is seldom discussed. In this paper, we present a new certificateless two party authentication key agreement protocol and prove its security attributes. Compared with the existing protocol, our protocol is more efficient.

Efficient Certificateless Authenticated Key Agreement Protocol from Pairings

In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/server setting is proposed, which uses pairings on certain elliptic curves. We show that the newly proposed key agreement protocol is practical and of great efficiency, meanwhile, it satisfies every desired security require ments for key agreement protocols.

Assessing Disagreement and Tolerance of Misclassification of Satellite-derived Land Cover Products Used in WRF Model Applications

As more satellite-derived land cover products used in the study of global change, especially climate modeling, assessing their quality has become vitally important. In this study, we developed a distance metric based on the parameters used in weather research and forecasting （WRF） to characterize the degree of disagreement among land cover products and to identify the tolerance for misclassification within the International Geosphere Biosphere Programme （IGBP） classification scheme. We determined the spatial degree of disagreement and then created maps of misclassification of Moderate Resolution Imaging Spectoradiometer （MODIS） products, and we calculated overall and class-specific accuracy and fuzzy agreement in a WRF model. Our results show a high level of agreement and high tolerance of misclassification in the WRF model between large-scale homogeneous landscapes, while a low level of agreement and tolerance of misclassification appeared in heterogeneous landscapes. The degree of disagreement varied significantly among seven regions of China. The class-specific accuracy and fuzzy agreement in MODIS Collection 4 and 5 products varied significantly. High accuracy and fuzzy agreement occurred in the following classes： water, grassland, cropland, and barren or sparsely vegetated. Misclassification mainly occurred among specific classes with similar plant functional types and low discriminative spectro-temporal signals. Some classes need to be improved further; the quality of MODIS land cover products across China still does not meet the common requirements of climate modeling. Our findings may have important implications for improving land surface parameterization for simulating climate and for better understanding the influence of the land cover change on climate.

Efficient Authenticated Key Agreement Protocol Using Self-Certified Public Keys from Pairings

An efficient authenticated key agreement protocol is proposed, which makesuse of bilinear pairings and self-certificd public keys. Its security is based on the securityassumptions of the bilinear Diff ie-Hellman problem and the computational Diffie-Hellman problem.Users can choose their private keys independently. The public keys and identities of users can beverified implicitly when the session key being generating in a logically single step. A trusted KeyGeneration Center is no longer requiredas in the ID-based authenticated key agreement protocolsCompared with existing authenticated key agreement protocols from pairings, the. new proposedprotocol is more efficient and secure.

Breaking and Repairing the Certificateless Key Agreement Protocol from ASIAN 2006

The certificateless authenticated key agreement protocol proposed by Mandt et al does not haVE the property of key-compromise impersonation （K-CI） resilience. An improved protocol with a simple modification of their protocol is proposed in this paper. In particular, our improved protocol is proved to be immune to the K-CI attack and at the same time possess other security properties.

Repeatability and agreement of CCT measurement in myopia using entacam and ultrasound pachymetry

AIM: To evaluate the repeatability of central corneal thickness (CCT) measurement by entacam, and agreement of CCT measured by Pentacam and ultrasound pachymetry (USP) in Chinese myopia. Thereby investigate the possibility of Pentacam as a substitute for USP in CCT measurement before refractive surgery. The effects of corneal curvature measured by Pentacam on CCT were also evaluated. METHODS: One hundred and forty-eight right eyes of 148 individual with myopia were included in this study. Three successive Pentacam CCT measurements followed by 10 successive ultrasound pachymetry were carried out in the 148 eyes. Mean of CCT taken by each device was calculated for comparison. According to the CCT measured by USP, all the 148 eyes were divided into 3 groups: <520 mu m, 520-560 mu m, >560 mu m. For all eyes and each group the CCT obtained by Pentacam and USP were compared. Anterior corneal curvature of the 148 eyes was also adopted for correlation analysis with CCT obtained by ultrasound pachymetry. In addition, CCT measurement using 60 random selected Scheimpflug images was performed by 3 skilled investigators at different time, and this was repeated for 3 times by a forth investigator to assess repeatability of Pentacam CCT measurement using Scheimpflug images. RESULTS: Intraclass correlation coefficient (ICC) analysis revealed high intraobserver repeatability (ICC=0.994, F=158.60, P<0.001) for CCT measurement by Pentacam. The interobserver (ICC=0.998, F =494.73, P <0.001) and intraobserver (ICC=0.997, F=383.98, P<0.001) repeatability for Pentacam CCT measurements using Scheimpflug images were also excellent. There was high positive correlation between the CCT values measured by Pentacam and ultrasound pachymetry (r=0.963, P<0.001). Bland-altman plots showed that the Pentacam underestimate the CCT by 8.02 mu m compared with ultrasouond pachymetry.The differences between Pentacam and USP increased as the CCT readings by USP increased (Pentacam vs USP: slope=-0.04, P< 0.05). The 95% upper and lower limits of agreement between CCT values obtained from the two devices were +9. 33 mu m and -25.37 mu m. No significant association could be found between CCT and anterior corneal curvature. CONCLUSION: Inter- and intraobserver variability for CCT measurements by Pentacam was considerably below clinically significant levels. CCT of myopia obtained by Scheimpflug camera, Pentacam, were highly correlated to that by ultrasound pachymetry. However, the values obtained are not directly interchangeable between Pentacam and ultrasound pachymetry as the 95% limits of agreement are relatively wide. Pentacam can be a useful instrument for measuring CCT in candidates to refractive surgery in clinic.

A Provably Secure Identity-based Authentication Multiple Key Agreement Protocol

An authentication multiple key agreement protocol allows the users to compute more than one session keys in an authentication way. In the paper,an identity-based authentication multiple key agreement protocol is proposed. Its authentication part is proven secure against existential forgery on adaptively chosen message and ID attacks under the random oracle model upon the CDH assumptions. The session keys are proven secure in a formal CK security model under the random oracle model upon the CBDH assumptions. Compared with the previous multiple key agreement protocols,it requires less communication cost.

The Homomorphic Key Agreement

There are various challenges that are faced in group communication, so it is necessary to ensure session key. Key agreement is the fundamental cryptographic primitive for establishing a secure communication. It is a process of computing a shared secret contributed by two or more entities such that no single node can predetermine the resulting value. An authenticated key agreement is attained by combining the key agreement protocol with digital signatures. After a brief introduction to existing key agreement in group communication, Making use of the additive-multiplicative homomorphism in the integer ring defined by Sander and Tschudin: A new protocols, called the homomorphism key agreement, was designed, which can be self-contributory, robust, scalable and applicable in group communication.