Written Chinese has tens of thousands of characters. But most available fonts contain only around... more Written Chinese has tens of thousands of characters. But most available fonts contain only around 6 to 12 thousand common characters that can meet the needs of everyday users. However, in publications and information exchange in many professional fields, a number of rare characters that are not in common fonts are needed in each document. This paper describes a method of typesetting such rare characters in LTEX. The document author describes a rare character in HanGlyph when such need arises. A Chinese character synthesis system renders the glyph according to this description and collects the newly created glyphs into a font so they are available in the body of the LTEX document.
Providing high data rates to wireless users has long been a goal that has driven the development ... more Providing high data rates to wireless users has long been a goal that has driven the development of new technologies and standards in the past decade. Now, with the opening up of the spectrum at 60 GHz, it has become possible to design WLANs that can meet the goal of Gbps/user connectivity. This paper examines several unique design challenges brought about because of the physical characteristics of this frequency band. We show that antenna geometry has a significant impact on throughput. Geometric SDMA algorithms are developed that yield an almost linear scaling of throughput with the number of users yielding 800 Mbps/user on average. We then explore the challenge of providing coverage in dead spots using the novel idea of passive reflectors. Finally, we examine the issue of power control and how the room geometry can be exploited to reduce the average energy/bit. The results presented are based on detailed PHY layer simulations of the 60 GHz system including accurate 3D beam patterns formed by the antennas.
In typical enterprise networks, a large fraction of ports see utilization of less than 5% at peak... more In typical enterprise networks, a large fraction of ports see utilization of less than 5% at peak times and close to zero utilization otherwise. Therefore, the normal architecture of one switch port per end-host is very wasteful because of the need for high port density switches to support numerous end users. In this paper we propose merging traffic from multiple end-hosts and feeding that to small port density switches that can replace the high port density switches. The energy savings from such a redesign are significant. The innovative part of this paper is the design of a low-power Merge network that is used to merge traffic from N incoming links to be fed to K switch ports and for sending traffic from the K-port switch to N links. Further, we present algorithms to enable network designers to re-architect their networks using the merge network, and a feasibility study using our College of Engineering network as a working example to illustrate how this approach would work and the resultant energy savings of almost 47%.
Tracking the movement of people in indoor environments is useful for a variety of applications in... more Tracking the movement of people in indoor environments is useful for a variety of applications including elderly care, study of shopper behavior in shopping centers, security etc. There have been several previous efforts at solving this problem but with limited success. Our approach uses inexpensive pressure sensors, placed in a specific manner, that allows us to identify multiple people. Given this information, our algorithm can track multiple people across the floor even in the presence of large sensor error. The algorithm we develop is evaluated for a variety of different movement patterns that include turning and path crossing. The error in correct path detection is shown to be very small even in the most complex movement scenario. We note that our algorithm does not use any a priori information such as weight, rfid tags, knowledge of number of people, etc.
Providing high data rates to wireless users has long been a goal that has driven the development ... more Providing high data rates to wireless users has long been a goal that has driven the development of new technologies and standards in the past decade. Now, with the opening up of the spectrum at 60 GHz, it has become possible to design WLANs that can meet the goal of Gbps/user connectivity. This paper examines several unique design challenges brought about because of the physical characteristics of this frequency band. We show that antenna geometry has a significant impact on throughput. This result is obtained when we utilize realistic 3D beam patterns, rather than the common 2D approximation. Indeed, the maximum average throughput for a linear antenna array of 8 Gbps (using only 640 MHz of spectrum) is more than double that obtained with a circular array consisting of the same number of antenna elements. We explore the challenge of providing coverage in dead spots using the novel idea of passive reflectors.
... Candy Yiu Department of Computer Science Portland State University Portland, OR 97207 http://... more ... Candy Yiu Department of Computer Science Portland State University Portland, OR 97207 http://www.cs.pdx.edu/∼candy ... A key architectural component of enterprise networks are the high fan-out switches which connect end users to the network. ...
Written Chinese has tens of thousands of characters. But most available fonts contain only around... more Written Chinese has tens of thousands of characters. But most available fonts contain only around 6 to 12 thousand common characters that can meet the needs of everyday users. However, in publications and information exchange in many professional fields, a number of rare characters that are not in common fonts are needed in each document. This paper describes a method of typesetting such rare characters in LTEX. The document author describes a rare character in HanGlyph when such need arises. A Chinese character synthesis system renders the glyph according to this description and collects the newly created glyphs into a font so they are available in the body of the LTEX document.
Providing high data rates to wireless users has long been a goal that has driven the development ... more Providing high data rates to wireless users has long been a goal that has driven the development of new technologies and standards in the past decade. Now, with the opening up of the spectrum at 60 GHz, it has become possible to design WLANs that can meet the goal of Gbps/user connectivity. This paper examines several unique design challenges brought about because of the physical characteristics of this frequency band. We show that antenna geometry has a significant impact on throughput. Geometric SDMA algorithms are developed that yield an almost linear scaling of throughput with the number of users yielding 800 Mbps/user on average. We then explore the challenge of providing coverage in dead spots using the novel idea of passive reflectors. Finally, we examine the issue of power control and how the room geometry can be exploited to reduce the average energy/bit. The results presented are based on detailed PHY layer simulations of the 60 GHz system including accurate 3D beam patterns formed by the antennas.
In typical enterprise networks, a large fraction of ports see utilization of less than 5% at peak... more In typical enterprise networks, a large fraction of ports see utilization of less than 5% at peak times and close to zero utilization otherwise. Therefore, the normal architecture of one switch port per end-host is very wasteful because of the need for high port density switches to support numerous end users. In this paper we propose merging traffic from multiple end-hosts and feeding that to small port density switches that can replace the high port density switches. The energy savings from such a redesign are significant. The innovative part of this paper is the design of a low-power Merge network that is used to merge traffic from N incoming links to be fed to K switch ports and for sending traffic from the K-port switch to N links. Further, we present algorithms to enable network designers to re-architect their networks using the merge network, and a feasibility study using our College of Engineering network as a working example to illustrate how this approach would work and the resultant energy savings of almost 47%.
Tracking the movement of people in indoor environments is useful for a variety of applications in... more Tracking the movement of people in indoor environments is useful for a variety of applications including elderly care, study of shopper behavior in shopping centers, security etc. There have been several previous efforts at solving this problem but with limited success. Our approach uses inexpensive pressure sensors, placed in a specific manner, that allows us to identify multiple people. Given this information, our algorithm can track multiple people across the floor even in the presence of large sensor error. The algorithm we develop is evaluated for a variety of different movement patterns that include turning and path crossing. The error in correct path detection is shown to be very small even in the most complex movement scenario. We note that our algorithm does not use any a priori information such as weight, rfid tags, knowledge of number of people, etc.
Providing high data rates to wireless users has long been a goal that has driven the development ... more Providing high data rates to wireless users has long been a goal that has driven the development of new technologies and standards in the past decade. Now, with the opening up of the spectrum at 60 GHz, it has become possible to design WLANs that can meet the goal of Gbps/user connectivity. This paper examines several unique design challenges brought about because of the physical characteristics of this frequency band. We show that antenna geometry has a significant impact on throughput. This result is obtained when we utilize realistic 3D beam patterns, rather than the common 2D approximation. Indeed, the maximum average throughput for a linear antenna array of 8 Gbps (using only 640 MHz of spectrum) is more than double that obtained with a circular array consisting of the same number of antenna elements. We explore the challenge of providing coverage in dead spots using the novel idea of passive reflectors.
... Candy Yiu Department of Computer Science Portland State University Portland, OR 97207 http://... more ... Candy Yiu Department of Computer Science Portland State University Portland, OR 97207 http://www.cs.pdx.edu/∼candy ... A key architectural component of enterprise networks are the high fan-out switches which connect end users to the network. ...
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