public Set<String> findSet(String woe_id,String group_id) {
		SearchParameters search_parameters = new SearchParameters();
		search_parameters.setWoeId(woe_id);

		Set<String> user_set = findUserSet(woe_id);
		Set<String> result = new HashSet<String>();
		PhotoList photo_list = null;

		System.out.println("total user:" + user_set.size());
		int user_count = 0;
		String str = "";
		int same_str = 0;

		for (String owner_id : user_set) {
			search_parameters.setUserId(owner_id);

			try {
				photo_list = photo_interface.search(search_parameters, 250, 1);
				int pages = photo_list.getPages();
				for (int i = 1; i <= pages; i++) {
					photo_list = photo_interface.search(search_parameters, 250,
							i);
					for (Object o : photo_list) {
						Photo photo = (Photo) o;
						String photo_id = photo.getId();
						Element photoElement = apiPhotosGetInfo(photo_id);
						String location = parseLocation(photoElement);
						System.out.println("location:" + location);
						if (str.equals(owner_id + "," + location))
							same_str++;
						if (same_str >= 30) {
							same_str = 0;
							continue;
						}
						str = owner_id + "," + location;
						result.add(str);
						System.out.println("collected count:" + result.size());
					}
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (SAXException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (FlickrException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			user_count++;
			System.out.println("done user:" + user_count);
		}

		return result;
	}