Context Maritime Surveillance (MS) has received increased attention from a civilian perspective in recent years. Anomaly detection (AD) is one of the many techniques available for improving the safety and security in the MS domain. Maritime authorities utilize various confidential data sources for monitoring the maritime activities; however, a paradigm shift on the Internet has created new sources of data for MS. These newly identified data sources, which provide publicly accessible data, are the open data sources. Taking advantage of the open data sources in addition to the traditional sources of data in the AD process will increase the accuracy of the MS systems. Objectives The goal is to investigate the potential open data as a complementary resource for AD in the MS domain. To achieve this goal, the first step is to identify the applicable open data sources for AD. Then, a framework for AD based on the integration of open and closed data sources is proposed. Finally, according to the proposed framework, an AD system with the ability of using open data sources is developed and the accuracy of the system and the validity of its results are evaluated. Methods In order to measure the system accuracy, an experiment is performed by means of a two stage random sampling on the vessel traffic data and the number of true/false positive and negative alarms in the system is verified. To evaluate the validity of the system results, the system is used for a period of time by the subject matter experts from the Swedish Coastguard. The experts check the detected anomalies against the available data at the Coastguard in order to obtain the number of true and false alarms. Results The experimental outcomes indicate that the accuracy of the system is 99%. In addition, the Coastguard validation results show that among the evaluated anomalies, 64.47% are true alarms, 26.32% are false and 9.21% belong to the vessels that remain unchecked due to the lack of corresponding data in the Coastguard data sources. Conclusions This thesis concludes that using open data as a complementary resource for detecting anomalous behavior in the MS domain is not only feasible but also will improve the efficiency of the surveillance systems by increasing the accuracy and covering some unseen aspects of maritime activities.
22, 23], (ii) reaction of ketals with H 2 O 2 in the presence of tungstic acid [24], or BF 3 ·Et 2 O [25], and (iv) peroxidation of ketones using an acidic solvent [26]. However, many of these methods have certain drawbacks including use of concentrated H 2 O 2 and excess acid, low yield, limited substrate range and production of mixtures of peroxidic products [27]. Also, poor selectivity and the presence of ozonesensitive groups in the substrates are further limitations in ozonolysis reaction. To avoid such limitations, recently, reactions of ketones and aldehydes with H 2 O 2 in the presence of Lewis acids in organic solvents have been reported. Among the Lewis acids, I 2 [28, 29], ceric ammonium nitrate (CAN) [30], CSA [31], NaHSO 4 ·SiO 2 [32], Re 2 O 7 [33], and PMA [34] have been reported as the catalysts in the synthesis of gem-dihydroperoxides with aqueous H 2 O 2 .In continuation of our efforts to explore new catalysts for synthesis of gem-dihydroperoxides [35,36]. Herein, we wish to introduce the sulfamic acid as a low-cost, green and effective recoverable solid catalyst in the synthesis of gemdihydroperoxides from ketones and aldehydes with 30 % aqueous H 2 O 2 at room temperature (Scheme 1).Sulfamic acid (SA) (NH 2 SO 3 H) is commercially available green heterogeneous catalyst that is solvable in water and has been used widely as an effective catalyst in organic synthesis [37,38].
ExperimentalSolvents, reagents, and chemical materials were obtained from Aldrich and Merck chemical companies and purified prior to use. Nuclear magnetic resonance spectra were recorded on JEOL FX 90Q using tetramethylsilane (TMS) as an internal standard. Infrared spectra were recorded on a PerkinElmer GX FT IR spectrometer (KBr pellets).Abstract Sulfamic acid has been used as an active, lowcost and reusable solid catalyst for conversion of ketones and aldehydes to corresponding gem-dihydroperoxides using 30 % aqueous hydrogen peroxide at room temperature. The reactions proceed with high rates and excellent yields.
Zinc chloride anhydrous has been used as an efficient and new catalyst for conversion of ketones and aldehydes to corresponding gem-dihydroperoxides by aqueous hydrogen peroxide (30%) in room temperature with excellent yields and notable reaction times.
An efficient acid‐catalyzed synthesis of some bis, tris, and tetrakis(indolyl)methanes, 3,4‐dihydropyrimidin‐2(1H)‐ones, and 2‐aryl‐1H‐benzothiazoles is reported using NaY zeolite functionalized by sulfamic acid/Cu(OAc)2 (NaY zeolite‐NHSO3H/Cu(OAc)2) in excellent yield. The heterogeneous catalyst has a simple work‐up procedure and could be recycled and reused for six reaction cycles.
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