Experimental Evaluation of Branching Schemes for the CSP

The search strategy of a CP solver is determined by the variable and value ordering heuristics it employs and by the branching scheme it follows. Although the effects of variable and value ordering heuristics on search effort have been widely studied, the effects of different branching schemes have received less attention. In this paper we study this effect through an experimental evaluation that includes standard branching schemes such as 2-way, d-way, and dichotomic domain splitting, as well as variations of set branching where branching is performed on sets of values. We also propose and evaluate a generic approach to set branching where the partition of a domain into sets is created using the scores assigned to values by a value ordering heuristic, and a clustering algorithm from machine learning. Experimental results demonstrate that although exponential differences between branching schemes, as predicted in theory between 2-way and d-way branching, are not very common, still the choice of branching scheme can make quite a difference on certain classes of problems. Set branching methods are very competitive with 2-way branching and outperform it on some problem classes. A statistical analysis of the results reveals that our generic clustering-based set branching method is the best among the methods compared.Comment: To appear in the 3rd workshop on techniques for implementing constraint programming systems (TRICS workshop at the 16th CP Conference), St. Andrews, Scotland 201

OROGRAPHIC EFFECT ON HEAVY RAINFALL IN CHALKIDIKI PENINSULA (GREECE) INDUCED BY A MEDITERRANEAN COLD FRONT: A CASE STUDY ON 7 to 8 OF OCTOBER 2000

Abstract. The exceptional heavy rainfall, in Chalkidiki peninsula-Greece, of 240 mm in a very short time period of 6 hours (380 mm in 24 hours) is analyzed. This area geographically located in the NW shores of the Aegean Sea, commonly has not the experience of frequent heavy rainfall events, and consequently the natural hydrographic network was not able to restrain this strong rainfall shock. Thus the result of the impact of this phenomenon was floods and damages in the properties of the residents with a very significant cost of hundredths thousands of Euros. This heavy rain phenomenon has been analyzed studying the role of the topography, the role of the nearby warm sea and the prevailing meteorological conditions resulting from the passage of the cold frond. This front was moving almost from south to north passing at first above the warm Aegean Sea surface, where it was supplied with huge amounts of water vapors, giving a total precipitable water value up to 32,0 mm. Then the very humid air forced uplifting, due to the intense relief of the mountainous peninsula, resulting to this torrential rainfall. All the relevant meteorological data and information about atmospheric instability, instability indexes and precipitable water available arising to from five upper air stations and the synoptic charts of surface, 850, 700, 500 and 300 hPa were analyzed in order to describe in details this heavy rain phenomenon

Inspection system for in use pesticide application equiupment in Greece. First three years of application

According to Directive 2009/128/EC, all member states should have inspected all in-use Pesticide Application Equipment (PAE) by November 2016. In Greece, Law 4036/2012 embodied the provisions of this Directive into Greek legislation, but unfortunately due to various reasons, the inspections were significantly delayed. Aim of the current study is to briefly present the inspection system of in-use PAE that was developed due to the aforementioned law and then provide the statistical results of the inspections until February 2018. The progress of the last two years was significant, but a lot of work remains to make the inspection system functional and unproblematic.According to Directive 2009/128/EC, all member states should have inspected all in-use Pesticide Application Equipment (PAE) by November 2016. In Greece, Law 4036/2012 embodied the provisions of this Directive into Greek legislation, but unfortunately due to various reasons, the inspections were significantly delayed. Aim of the current study is to briefly present the inspection system of in-use PAE that was developed due to the aforementioned law and then provide the statistical results of the inspections until February 2018. The progress of the last two years was significant, but a lot of work remains to make the inspection system functional and unproblematic

OROGRAPHIC EFFECT ON HEAVY RAINFALL IN CHALKIDIKI PENINSULA (GREECE) INDUCED BY A MEDITERRANEAN COLD FRONT: A CASE STUDY ON 7 to 8 OF OCTOBER 2000

Abstract. The exceptional heavy rainfall, in Chalkidiki peninsula-Greece, of 240 mm in a very short time period of 6 hours (380 mm in 24 hours) is analyzed. This area geographically located in the NW shores of the Aegean Sea, commonly has not the experience of frequent heavy rainfall events, and consequently the natural hydrographic network was not able to restrain this strong rainfall shock. Thus the result of the impact of this phenomenon was floods and damages in the properties of the residents with a very significant cost of hundredths thousands of Euros. This heavy rain phenomenon has been analyzed studying the role of the topography, the role of the nearby warm sea and the prevailing meteorological conditions resulting from the passage of the cold frond. This front was moving almost from south to north passing at first above the warm Aegean Sea surface, where it was supplied with huge amounts of water vapors, giving a total precipitable water value up to 32,0 mm. Then the very humid air forced uplifting, due to the intense relief of the mountainous peninsula, resulting to this torrential rainfall. All the relevant meteorological data and information about atmospheric instability, instability indexes and precipitable water available arising to from five upper air stations and the synoptic charts of surface, 850, 700, 500 and 300 hPa were analyzed in order to describe in details this heavy rain phenomenon

Wyspa ciepła i wskaźniki bioklimatyczne w Salonikach

The intensity of the heat island in the city of Thessaloniki,during the period 1950-1995, is studied. Daily data of minimum air temperature in one urban (AUTH) and one rural station (Macedonia air port) were used to estimate the monthly course of the heat island effect during the last 46 years. The resulting graphs show the existence of an intense heat island phenomenon in the city of Thessaloniki, as the daily temperature differences (Tu-Tr), in some cases exceed the ±6°C and the monthly magnitudes come up to ±4°C. Also, the monthly courses of the wind-chilltemperature in the city of Thessaloniki, for a period of 50 years (1946-1995),is analyzed. The march of the wind-<:hilltemperature shows that not any pronounced fluctuation exists during the warm period, probably due to the contrariwise behavior of the city on the magnitudes of the temperature and wind parameters, but during the colder months it exists a positive effect on the mildness of the city climate.Badano intensywność miejskiej wyspy ciepła w Salonikach w okresie 1950--1995. Dobowe dane o minimalnej temperaturze powietrza ze stacji miejskiej i zamiejskiej wykorzystano w celu oceny miesięcznego przebiegu efektu wyspy ciepła w ciągu ostatnich 46 lat. Uzyskane wykresy wskazują na istnienie intensywnej wyspy ciepła w Salonikach w niektórych przypadkach przekraczającej natężenie 6°C (różnice temperatury Tu- Tr), a wartości miesięczne dochodzą do ±4°C. Analizowano również miesięczne przebiegi wskażnika ochładzania wiatrem w Salonikach dla okresu 50 lat (1946-1995). W chłodnych miesiącach roku w świetle tego wskaźnika stwierdzono efekt złagodzenia klimatu miasta