Energy-Efficient Broadcasting in All-Wireless Networks

In all-wireless networks, minimizing energy consumption is crucial as in most cases the nodes are battery-operated. We focus on the problem of power-optimal broadcast, for which it is well known that the broadcast nature of radio transmissions can be exploited to optimize energy consumption. This problem appears to be difficult to solve [30]. We provide a formal proof of NP-completeness for the general case and give an NP-completeness result for the geometric case; in the former, the network topology is represented by a generic graph with arbitrary weights, whereas in the latter a Euclidean distance is considered. For the general case, we show that it cannot be approximated better than O(log N), where N is the total number of nodes. We then describe an approximation algorithm that achieves the O(log N) approximation ratio. We also describe a new heuristic, Embedded Wireless Multicast Advantage. We show that it compares well with other proposals and we explain how it can be distribute

SSSL: Shoulder Surfing Safe Login

Classical PIN-entry methods are vulnerable to a broad class of observation attacks (shoulder surfing, key-logging). A number of alternative PIN-entry methods that are based on human cognitive skills have been proposed. These methods can be classified into two classes regarding information available to a passive adversary: (i) the adversary fully observes the entire input and output of a PIN-entry procedure, and (ii) the adversary can only partially observe the input and/or output. In this paper we propose a novel PIN-entry scheme- Shoulder Surfing Safe Login (SSSL). SSSL is a challenge response protocol that allows a user to login securely in the presence of the adversary who can observe (via key-loggers, cameras) user input. This is accomplished by restricting the access to SSSL challenge values. Compared to existing solutions, SSSL is both user-friendly (not mentally demanding) and cost efficient. Our usability study reveals that the average login time with SSSL is around 8 sec in a 5-digit PIN scenario. We also show the importance of considering side-channel timing attacks in the context of authentication schemes based on human cognitive skills

Fortune cookies and smartphones: Weakly unrelayable channels to counter relay attacks

Smartphones are being increasingly used to perform financial transactions (through m-banking, virtual wallet or as a smartcard). The latter applications involve contactless technology (e.g., NFC) that is known to be vulnerable to mafia fraud attacks. In this work we show that a secret message inside an appropriately folded piece of paper (fortune cookie) can be used to effectively mitigate the mafia fraud attack. Fortune cookies implement a weakly unrelayable channel that, in combination with smartphones, provides a provable protection against those attacks. Our solution requires minimal or no hardware changes to the existing equipment (especially on the user’s side) and is suitable for different communication technologies (e.g., intra-body communication, NFC, WiFi, Bluetooth, sound, infrared)

Urban Development of Split in SFR Yugoslavia

Split je naširoko poznat kao grad koji se razvio unutar i naokolo Dioklecijanove palače. Kroz veći dio svog postojanja, grad se nije značajno širio u prostoru, ali situacija se počela mijenjati nakon završetka Prvog svjetskog rata. Tada započinje gospodarski i populacijski uzlet Splita koji se počinje širiti na okolna polja koja su ga stoljećima okruživala. Sve je prekinuto Drugim svjetskim ratom nakon kojeg dolazi do promjene društveno-političkog uređenja čime započinje novo razdoblje urbanog razvoja. Riječ je o razdoblju od 1945. do 1991. koje je predmet istraživanja ovog rada. U promijenjenim okolnostima Split doživljava populacijski uzlet neviđenih razmjera koji biva popraćen s obimnom stambenom izgradnjom. U radu su prikazane i analizirane različite faze urbanog razvoja u promatranom razdoblju u kojem se drastično izmijenila vizura dotadašnjeg tipičnog mediteranskog gradića u grad kakvog danas poznajemo.Split is widely known as the city that was formed around Diocletian's Palace. For the next millennium and a half, Split encompassed mostly the same initially built-up area, but that started to change after World War I. It was a beginning of economic and population boom of the city that started to spread out onto surrounding areas. Development was halted by World War II after which Split became part of SFR Yugoslavia. Urban development of Split in SFR Yugoslavia from 1945 to 1991 is the topic of this thesis. In this period population of Split grew rapidly and was followed by extensive urban and construction projects. The aim of this thesis is to analyze different stages of urban development in this period

Urban Development of Split in SFR Yugoslavia

Split je naširoko poznat kao grad koji se razvio unutar i naokolo Dioklecijanove palače. Kroz veći dio svog postojanja, grad se nije značajno širio u prostoru, ali situacija se počela mijenjati nakon završetka Prvog svjetskog rata. Tada započinje gospodarski i populacijski uzlet Splita koji se počinje širiti na okolna polja koja su ga stoljećima okruživala. Sve je prekinuto Drugim svjetskim ratom nakon kojeg dolazi do promjene društveno-političkog uređenja čime započinje novo razdoblje urbanog razvoja. Riječ je o razdoblju od 1945. do 1991. koje je predmet istraživanja ovog rada. U promijenjenim okolnostima Split doživljava populacijski uzlet neviđenih razmjera koji biva popraćen s obimnom stambenom izgradnjom. U radu su prikazane i analizirane različite faze urbanog razvoja u promatranom razdoblju u kojem se drastično izmijenila vizura dotadašnjeg tipičnog mediteranskog gradića u grad kakvog danas poznajemo.Split is widely known as the city that was formed around Diocletian's Palace. For the next millennium and a half, Split encompassed mostly the same initially built-up area, but that started to change after World War I. It was a beginning of economic and population boom of the city that started to spread out onto surrounding areas. Development was halted by World War II after which Split became part of SFR Yugoslavia. Urban development of Split in SFR Yugoslavia from 1945 to 1991 is the topic of this thesis. In this period population of Split grew rapidly and was followed by extensive urban and construction projects. The aim of this thesis is to analyze different stages of urban development in this period

Urban Development of Split in SFR Yugoslavia

Split je naširoko poznat kao grad koji se razvio unutar i naokolo Dioklecijanove palače. Kroz veći dio svog postojanja, grad se nije značajno širio u prostoru, ali situacija se počela mijenjati nakon završetka Prvog svjetskog rata. Tada započinje gospodarski i populacijski uzlet Splita koji se počinje širiti na okolna polja koja su ga stoljećima okruživala. Sve je prekinuto Drugim svjetskim ratom nakon kojeg dolazi do promjene društveno-političkog uređenja čime započinje novo razdoblje urbanog razvoja. Riječ je o razdoblju od 1945. do 1991. koje je predmet istraživanja ovog rada. U promijenjenim okolnostima Split doživljava populacijski uzlet neviđenih razmjera koji biva popraćen s obimnom stambenom izgradnjom. U radu su prikazane i analizirane različite faze urbanog razvoja u promatranom razdoblju u kojem se drastično izmijenila vizura dotadašnjeg tipičnog mediteranskog gradića u grad kakvog danas poznajemo.Split is widely known as the city that was formed around Diocletian's Palace. For the next millennium and a half, Split encompassed mostly the same initially built-up area, but that started to change after World War I. It was a beginning of economic and population boom of the city that started to spread out onto surrounding areas. Development was halted by World War II after which Split became part of SFR Yugoslavia. Urban development of Split in SFR Yugoslavia from 1945 to 1991 is the topic of this thesis. In this period population of Split grew rapidly and was followed by extensive urban and construction projects. The aim of this thesis is to analyze different stages of urban development in this period