Classifiers accuracy improvement based on missing data imputation

In this paper we investigate further and extend our previous work on radar signal identification and classification based on a data set which comprises continuous, discrete and categorical data that represent radar pulse train characteristics such as signal frequencies, pulse repetition, type of modulation, intervals, scan period, scanning type, etc. As the most of the real world datasets, it also contains high percentage of missing values and to deal with this problem we investigate three imputation techniques: Multiple Imputation (MI); K-Nearest Neighbour Imputation (KNNI); and Bagged Tree Imputation (BTI). We apply these methods to data samples with up to 60% missingness, this way doubling the number of instances with complete values in the resulting dataset. The imputation models performance is assessed with Wilcoxon’s test for statistical significance and Cohen’s effect size metrics. To solve the classification task, we employ three intelligent approaches: Neural Networks (NN); Support Vector Machines (SVM); and Random Forests (RF). Subsequently, we critically analyse which imputation method influences most the classifiers’ performance, using a multiclass classification accuracy metric, based on the area under the ROC curves. We consider two superclasses (‘military’ and ‘civil’), each containing several ‘subclasses’, and introduce and propose two new metrics: inner class accuracy (IA); and outer class accuracy (OA), in addition to the overall classification accuracy (OCA) metric. We conclude that they can be used as complementary to the OCA when choosing the best classifier for the problem at hand

Печати на Торник протоспатарий и стратег на Калудия

The paper presents a seal of Tornikos, protospatharios and strategos of Caludia which is with unclear provenance. This new seal is the third known specimen in excellent state of preservation. Thus allow to correct the inscriptions from other two specimens – from Istanbul and Taman peninsula. The seal call in question nowadays dating of these seals – (1030–1038) as well as the attempts to identify its owner with the strategos of Edessa in 1038 – Tornikos Iviros. He is mentioned by John Skylitzes in his History. All three specimens were sent to three different addressees because they were found on a big distance from each other. It is hard to believe that they were sent to one receiver who moved from one place to another. It is hard to say who these addressees were. To whom and why in nowadays Bulgaria and Taman peninsula he wrote the letters. There was no any administrative connection between them. Perhaps Tornikos, protospatharios and strategos of Caludia wrote to his colleagues or relatives which sojourned in different parts of the Empire.В статье публикуется печать Торника, императорского протоспафария и стратига Калудия. Она происходит с территории Болгарии, но точное место находки неизвестно. Это третий из моливдовулов Торника. Благодаря его отличной сохранности можно скорректировать чтение надписей на двух других образцах – из Стамбула и с Таманского полуострова. В историографии пред-принимались попытки датировать печать 1030–1038 гг., а также идентифицировать его владельца со стратигом Эдессы в 1038 году – Торником Ивиром. Он упоминается в хронике Иоанна Скилицы. Автор статьи обращает внимание, что три экземпляра печати были отправлены трем различным адресатам, они были найдены на большом расстоянии друг от друга. Определить адресатов писем, как в Болгарии, так и на Таманском полуострове, он написал письма не представляется возможным. Во всяком случае, меж-ду этими территориями в первой половине XI в. не было никакой административной связи. Возможно, Торник, протоспафарий и стратиг Калудия писал своим родственникам, которые проживали в разных частях империи

Печатите на Теодорокан, патриций и катепан на Едеса (средата на ХІ в.)

There are two specimens, strike by one bulotirion. The first specimen is keeping in the Ashmoleon Museum in Oxford. It`s origin is probably from Gaziantep, Turkey. The other one is found during the archaeological excavations in Pliska. The seal is dated after the middle of 11th c. Who is that Theodorocanos and when exactly he was a katepano of Edessa? Is this a person familiar to us? Personal or family name refers? On the metrical texts so offend, the family name is write out. Several deputies of that family are known during the 11th c. unfortunately we cannot identify anyone. It is possible a third person with family or personal name could be presented on our seal. What is the connection between the seal of Theodorocan patrikios and katepano of Edessa and its finding in Pliska? May be he wrote from Edessa to his relative or friend in Pliska. Or he came on the Balkans with his troops for some special military operation. I thing the last is more possible solution.В статье публикуются два моливдовула, отчеканенные одним и тем же буллотирием. Один из них хранится в коллекции Ashmoleon Museum (Oxford), предполагается, что его происхождение связано с Газиантепом в Турции. Второй был найден во время раскопок в Плиске. Обе печати принадлежали катепану Эдессы Феодорокану, датируются они 50-ми гг. ХІ в. По письменным источникам и данным сфрагистики известны несколько представителей фамилии Феодороканов, однако точная идентификация кого-либо из них с владельцем печати невозможна