title: Modelling of wave climate and sediment transport patterns at a tideless embayed beach, Pirita Beach, Estonia

authors: Soomere, Tarmo

subjects: sediment transport

abstract: Nearshore sand transport patterns along the tideless, embayed Pirita beach, Tallinn, Estonia, have been investigated utilizing high-resolution modelling of wave processes combined with bathymetric surveys and sediment textural analyses of the nearshore sea floor. Textural analysis showed the mean grain size is about 0.12 mm. Fine sand (0.063–0.125 mm) accounts for about 77% of the sediments. Coarser-grained sand (0.28 mm) dominates along the waterline. Based upon the spatial distribution of the mean grain size and basic features of the local wave activity, properties of the Dean Equilibrium Beach Profile were determined.
Alongshore sediment transport was calculated based upon a long-term time series of wave properties along the beach, and the CERC formula applied to about 500 m long beach sectors. The time series of wave fields and the properties of the local wave climate were modelled using a triple nested WAM wave model with an extended spectral range for short waves. The model is forced by open sea wind data from Kalbådagrund for the years 1981–2002. Results indicate that typical closure depth at Pirita is 2.5 m. The width and mean slope of the equilibrium profile are 250 m and 1:100, respectively. Southward transport dominates in the northern sections of the beach whereas no prevailing transport direction exists in the southern sections. This pattern has several nontrivial implications for the planning of beach protection activities.

text: Modelling of wave climate and sediment transport patterns at a tideless embayed beach, Pirita Beach, Estonia Nearshore sand transport patterns along the tideless, embayed Pirita beach, Tallinn, Estonia, have been investigated utilizing high-resolution modelling of wave processes combined with bathymetric surveys and sediment textural analyses of the nearshore sea floor. Textural analysis showed the mean grain size is about 0.12 mm. Fine sand (0.063–0.125 mm) accounts for about 77% of the sediments. Coarser-grained sand (0.28 mm) dominates along the waterline. Based upon the spatial distribution of the mean grain size and basic features of the local wave activity, properties of the Dean Equilibrium Beach Profile were determined.
Alongshore sediment transport was calculated based upon a long-term time series of wave properties along the beach, and the CERC formula applied to about 500 m long beach sectors. The time series of wave fields and the properties of the local wave climate were modelled using a triple nested WAM wave model with an extended spectral range for short waves. The model is forced by open sea wind data from Kalbådagrund for the years 1981–2002. Results indicate that typical closure depth at Pirita is 2.5 m. The width and mean slope of the equilibrium profile are 250 m and 1:100, respectively. Southward transport dominates in the northern sections of the beach whereas no prevailing transport direction exists in the southern sections. This pattern has several nontrivial implications for the planning of beach protection activities.

year: 2008

title: Simulation with real world network stacks

authors: Jansen, Sam

subjects: computer science

abstract: Network simulation is used widely in network research to test new protocols, modifications to existing protocols and new ideas. The tool used in many cases is ns-2. The nature of the ns-2 protocols means that they are often based on theoretical models that might not behave in the same way as real networks. This paper presents the Network Simulation Cradle which allows real world network stacks to be used in a wrapper that allows the stacks protocols to be used in the ns-2 network simulator. The network stacks from the open source operating systems Linux, FreeBSD and OpenBSD are included in the simulation cradle as well as a stack designed for embedded systems, lwIP. Our results show that ns-2's TCP implementations do not match observed behaviour from real machines in some respects and using the Network Simulation Cradle produces results closer to real world network stacks.

text: Simulation with real world network stacks Network simulation is used widely in network research to test new protocols, modifications to existing protocols and new ideas. The tool used in many cases is ns-2. The nature of the ns-2 protocols means that they are often based on theoretical models that might not behave in the same way as real networks. This paper presents the Network Simulation Cradle which allows real world network stacks to be used in a wrapper that allows the stacks protocols to be used in the ns-2 network simulator. The network stacks from the open source operating systems Linux, FreeBSD and OpenBSD are included in the simulation cradle as well as a stack designed for embedded systems, lwIP. Our results show that ns-2's TCP implementations do not match observed behaviour from real machines in some respects and using the Network Simulation Cradle produces results closer to real world network stacks.

year: 2005

title: Interface of gender and culture

authors: Tamasese, Kiwi

subjects: Maori

abstract: I greet you in the soothing waters of the Pacific. The birth waters of Hawai’i to the North, island of the dream time, and Aotearoa, to the south. Papua New Guinea to the West and Marquesas to the East.  These islands are the gathering places of the world’s largest Continent, the Pacific. We of this continent know that her birth waters are our connection.  We also know that she is woman identified. It is no surprise therefore that from Hawai’i to the north to Aotearoa in the south the positioning of women in each of these societies bears a different story to that of the women of the continent of Europe.  This reality lived out in Hawai’i means women shared with men the ultimate leadership of peoples.  This location of women power is named Kuhinanui. Many remarkable women of Hawai’i occupied this position.  From times of peace throughout to the first clash with imposed new culture, women of Hawai’i led, bled, struggled, defied and kept the kukui of self belief burning. Genealogically Hawai’i is connected to her other sisters throughout the Pacific.  The story of Kuhinanui Liliuokalani is poignant.

text: Interface of gender and culture I greet you in the soothing waters of the Pacific. The birth waters of Hawai’i to the North, island of the dream time, and Aotearoa, to the south. Papua New Guinea to the West and Marquesas to the East.  These islands are the gathering places of the world’s largest Continent, the Pacific. We of this continent know that her birth waters are our connection.  We also know that she is woman identified. It is no surprise therefore that from Hawai’i to the north to Aotearoa in the south the positioning of women in each of these societies bears a different story to that of the women of the continent of Europe.  This reality lived out in Hawai’i means women shared with men the ultimate leadership of peoples.  This location of women power is named Kuhinanui. Many remarkable women of Hawai’i occupied this position.  From times of peace throughout to the first clash with imposed new culture, women of Hawai’i led, bled, struggled, defied and kept the kukui of self belief burning. Genealogically Hawai’i is connected to her other sisters throughout the Pacific.  The story of Kuhinanui Liliuokalani is poignant.

year: 1993