The Dynamics of Group Codes: Dual Abelian Group Codes and Systems

Fundamental results concerning the dynamics of abelian group codes (behaviors) and their duals are developed. Duals of sequence spaces over locally compact abelian groups may be defined via Pontryagin duality; dual group codes are orthogonal subgroups of dual sequence spaces. The dual of a complete code or system is finite, and the dual of a Laurent code or system is (anti-)Laurent. If C and C^\perp are dual codes, then the state spaces of C act as the character groups of the state spaces of C^\perp. The controllability properties of C are the observability properties of C^\perp. In particular, C is (strongly) controllable if and only if C^\perp is (strongly) observable, and the controller memory of C is the observer memory of C^\perp. The controller granules of C act as the character groups of the observer granules of C^\perp. Examples of minimal observer-form encoder and syndrome-former constructions are given. Finally, every observer granule of C is an "end-around" controller granule of C.Comment: 30 pages, 11 figures. To appear in IEEE Trans. Inform. Theory, 200

The National Juvenile Online Victimization Study: Methodology Report.

The National Juvenile Online Victimization Study (N‐JOV) was conducted by the Crimes against Children Research Center at the University of New Hampshire. Wave 1 of this study was funded by the National Center for Missing & Exploited Children and the Office of Juvenile Justice & Delinquency Prevention, U.S. Department of Justice. Wave 2 of this study was funded through grants from the Office of Juvenile Justice and Delinquency Prevention, U.S. Department of Justice. Researchers collected information from a national sample of law enforcement agencies about the prevalence of arrests for, and characteristics of, Internet sex crimes against minors in the criminal justice system in the 12 months following July 1, 2000 and again in calendar year 2006. The goal of this methodology was to : 1) utilize a representative national sample of law enforcement agencies that would give us an overall picture of these crimes in the United States, 2) understand how these cases emerged and were handled in a diverse group of agencies, 3) get detailed data about the characteristics of these crimes from well‐informed, reliable sources, and 4) see how the prevalence and characteristics of such crimes may have changed in a 5 to 6‐year time frame. For both Waves 1 and 2, we used a two‐phase process to collect data from a national sample of the same local, county, state, and federal law enforcement agencies. In Phase 1, we sent mail surveys to a national sample of law enforcement agencies asking if they had made arrests for Internet sex crimes against minors in a specific one‐year time frame. In Phase 2, we conducted telephone interviews with law enforcement investigators about a sample of the arrest cases reported in the mail survey. The final data set, weighted to account for sampling procedures and other factors, includes data from 612 completed case‐level interviews from Wave 1 and 1,051 different completed case‐level interviews from Wave 2

Internet Sex Crimes Against Minors: The Response of Law Enforcement.

The Internet1 and computers have come to play a growing role in sex crimes that are committed against children and youth.2 Since the mid-1990s these developing technologies have posed challenges for law enforcement requiring them to confront situations not anticipated in criminal statutes, master technical advances, develop new investigative techniques, and handle criminal cases that often span multiple jurisdictions. To assist, legislators have acted on a number of fronts creating new statutes that encompass Internet offenses, stiffening penalties, and creating a national clearinghouse for reports of Internet-related crimes against children and the CyberTipline® operated by the National Center for Missing & Exploited Children. In addition the federal government has increased funding in this area creating Internet Crimes Against Children Task Forces to support state and local law enforcement and specialized Internet, child-exploitation units in federal, law-enforcement agencies. Unfortunately the results of these initiatives are difficult to track. Criminaljustice authorities do not collect information specifically about Internet-related crimes. The National Juvenile Online Victimization (N-JOV) Study was undertaken to get a sense of the scope and types of law-enforcement activity in this area and serve as a baseline for monitoring the growth of Internet sex crimes against minors and related law-enforcement activities

National Juvenile Online Victimization Study (N-JOV): Methodology Report.

The National Juvenile Online Victimization Study (N-JOV Study) was conducted by the Crimes against Children Research Center at the University of New Hampshire, under grants from the National Center for Missing & Exploited Children and the Office of Juvenile Justice and Delinquency Prevention, U.S. Department of Justice. The N-JOV study collected information from a national sample of law enforcement agencies about the characteristics of Internet sex crimes against minors and the numbers of arrests for these crimes during a one-year period. The goals of our methodology were to 1) design a representative national sample of law enforcement agencies that would give us an overall picture of these crimes in the U.S., 2) understand how these cases emerged and were handled in a diverse group of agencies, and 3) get detailed data about the characteristics of these crimes from well-informed, reliable sources. We used a two-phase process to collect data from a national sample of local, county, state and federal law enforcement agencies. In Phase 1, we sent a mail survey to a national sample of law enforcement agencies asking if they had made arrests in Internet-related child pornography or sexual exploitation cases between July 1, 2000 and June 30, 2001. In Phase 2, we conducted telephone interviews with law enforcement investigators about a sample of the cases reported in the mail survey. The final data set, weighted to account for sampling procedures and other factors, includes data from 612 completed interviews