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Benvinguts a Barcelona! We are excited to introduce the Technical Program of the ACM International Conference on Multimedia 2013. This year, we built upon the guidelines from previous editions of the conference and introduced several new procedures and policies with the goal of improving the quality of the review process, the feedback provided to the authors, and the overall diversity of the technical program.

As in the last couple of years, the conference review process was structured with a two-tier Technical Program Committee. Following a discussion process that involved the General Chairs and the Program Chairs, we revised and expanded the list of areas from last year's conference and defined 12 areas for 2013 to bring topic diversity and growth to the conference: Art, Entertainment and Culture; Authoring and Collaboration; Crowdsourcing; Media Transport and Delivery; Mobile and Multi-Device; Multimedia Analysis; Multimedia HCI; Music and Audio; Search, Browsing, and Discovery; Security and Forensics; Social Media and Presence; and Systems and Middleware.

The Technical Program Committee was first created by appointing Area Chairs (ACs). A total of 29 colleagues agreed to serve in this role. Each Area was represented by two ACs, with exception of two Areas (Multimedia Analysis and Search, Browsing, and Discovery) whose scope has traditionally attracted the largest proportion of papers and so required further coordination. The added topic diversity brought an increase in gender diversity to the ACs, which increased from approximately 12% in previous years to 22% for 2013. We also made a conscious effort to bring new talent and excellence into the community and to better represent emerging trends in the field. For this we appointed many young and well recognized ACs who served in this role for the first time. For each junior AC, we co-appointed a senior researcher as their co-AC to aid in their shepherding. In a second step, the Area Chairs were responsible for appointing the TPC members (reviewers) for their coordinated areas. This was a large effort to grow the TPC base for the conference as well as ensure proper expertise was represented in each area. We coupled this with a hard goal of limiting the number of submissions assigned to each TPC member for review. For example, two years ago, the average number of papers assigned to a reviewer was 9 with over 38% of the approximately 225 TPC members receiving 10 or more papers to review. With our design, we had a total of 398 reviewers receiving an average of 4.13 papers per reviewer. While we were unable to keep a hard ceiling limitation, only 2.51% of the TPC received 10 or more papers to review-all TPC members who had agreed to serve in more than one area. The Area Chairs were in charge of assigning all papers for review, and each submission was reviewed double-blind by three TPC members. Reviews and reviewer assignments of papers co-authored by Area Chairs, Program Chairs, and General Chairs were handled by Program Chairs who had no conflicts of interest for each specific case.

Another novelty introduced in the reviewing process was to set the paper submission deadline to a significantly earlier date than previous years, in order to allocate more time for reviews, rebuttals, discussions, and final decisions. Despite the reduced time given to authors, the response to the Call for Papers was enthusiastic with a total of 235 long papers and 278 short papers going through review.

The authors of long papers were asked to write a rebuttal after receiving the reviews. A new element in the reviewing process was the introduction of the Author's Advocate figure, created to provide authors with an independent channel to express concerns about the quality of the reviews for their papers, and to raise a flag about these reviews. All cases were brought to the attention to the corresponding Area Chair. After evaluating each case reported to him (16 reviews out of 761 long paper reviews), the Author's Advocate recommended in 5 cases that new reviews were generated and added to the discussion. The reviewers had a period for on-line discussion of reviews and rebuttals, after which the Area Chairs drafted a meta-review for each paper.

Decisions on long and short papers were made at the TPC meeting held at the University of Amsterdam on June 11, 2013. The meeting was physically attended by one of the General Chairs, three of the Program Chairs, the Author's Advocate, and 86% of the ACs. Many of the ACs who were unable to attend were tele-present online for discussions. On the first half day of the TPC meeting, the Area Chairs worked in breakout sessions to discuss the papers that were weak accepts and weak rejects, with the exception of conflict of interest papers which were handled out of band as previously mentioned. In the second half of the first day, the ACs met in a plenary session where they reviewed the clear accepts and defended the decisions on the borderline papers based on the papers themselves, reviews, meta-reviews, on-line discussions, and authors' rebuttal comments. In many cases, an emergency reviewer was added if there was clear intersection with a related submission area. If a paper had any conflict of interest during the plenary session with an Area, Program, or General Chair, they were excused from the room. On June 12, 2013, the Program Chairs finalized the process and conference program in a separate meeting---arranging the sessions by thematic narratives and not by submission area to promote cross-area conversations during the conference itself.

The review process resulted in an overall acceptance rate of 20.0% for long papers and 27.7% for short papers. All accepted long papers were shepherded by the Area Chairs themselves or by qualified TPC members who were in charge of verifying that the revised papers adequately addressed concerns raised by the reviewers and changes promised by authors in their rebuttals. This step ensured that all of the accepted papers are of the highest quality possible. In addition, four papers with high review scores were nominated at the TPC meeting as candidates for the Best Paper Award. Each nominated paper had to be successfully championed and defended by the ACs from that area. The winner will be announced at the Conference Banquet.