Computer products maker Concurrent Technologies saw profits rise for the half year as the defence business continued to contribute strongly, while demand from commercial customers were weaker during the recession.Profit before tax rose 13% to £1.3m on sales that rose to £6.5m from £5.4m in the same period last year. The group said it continues to expect its 2009 overall financial performance to be satisfactory, adding that it viewed the subdued operating environment as being a short term factor."Indeed the future beyond this year looks positive in the part of the defence market in which we operate. We continue, for example to see very strong interest in our products for projects involving electronic, aerial and battlefield surveillance," said the group.Interim dividend was raised 11% to 0.50p