Question: what does asu stand for in signal strength
[{'answer': 'Arbitrary Strength Unit', 'provenance': [{'wikipedia_id': '13913552', 'title': 'Mobile phone signal', 'start_paragraph_id': 22, 'start_character': 0, 'end_paragraph_id': 22, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::ASU.\n'}]}, {'provenance': [{'wikipedia_id': '13913552', 'title': 'Mobile phone signal', 'start_paragraph_id': 22, 'start_character': 0, 'end_paragraph_id': 22, 'end_character': 123, 'bleu_score': 0.8970773746801091, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 401544505687681212}, 'section': 'Section::::ASU.\n'}]}]