Juho Määttä

User-centered design of graphical user interfaces

In user interface design a common pitfall is to use the technical properties of the device as basis for the design, which easily causes a user interface to become too complicated and hard to use. Also, the great development in the area of different hand-held terminal devices has set new requirements for user interfaces: screen sizes of devices are very small, advanced I/O devices are used instead of ordinary mouse and keyboard and the operating environment of the devices differs significantly from familiar PCs and laptops. However, governmental and in particular military communications systems often trail behind this development. To be able to overcome the aforementioned challenges and take usability of governmental communication systems to a new level, a new approach is needed. This paper covers user-centered design of graphical user interfaces to advanced communication devices designed to be used in challenging environment, e.g., in moving vehicles and outdoors in any season, and to support devices with limited screen size and touch screen technology. We also introduce a proof-of-concept implementation and show through a user test that general principles introduced in the paper can easily be applied to a specialized communication device.

The virtual network system

A popular technology area quickly gains competing solutions to solve the same goal. Examples include file systems and storage, and communication technologies. All competing solutions typically introduce their own specific functionality, programming models and APIs; this generally forces application programmers to choose a specific solution and build the application for it. There exists exceptions to this unfortunate state of affairs, e.g., Linux includes the Virtual File System (VFS) to decouple applications from specific local storage devices. A similar functionality is provided by the Network File System (NFS), i.e., it decouples the client from the storage server. The communication technologies do not have a similar solution: each technology is different and has its own programming model and API. In this paper we introduce the Virtual Network System (VNS) that combines the concepts of VFS and NFS for communication technologies. Our solution is a middleware that enables a unified API for applications to use any communication technology, local or remote. We describe our architecture and discuss our current implementation that enables communication over IP and VHF radio.

Email Messaging over Heterogeneous Networks and Interfaces

Communication from a device with multiple interfaces is not a new concept, e.g., we have mobile phones with multiple radios, or laptops with Ethernet, WLAN and 3G connectivity. Mobile IP (MIP) is the primary mechanism to enable seamless communication and switching over multiple interfaces. This is possible since all the interfaces support the Internet Protocol, and have a common addressing scheme, a unified network and transport layers. MIP is a well understood and mature solution. However, when communication should happen over multiple interfaces, where the only common denominator is the ability to transfer bits, most of the OSI-layers below the application layer differ.Thus, MIP or any similar IP-based technology can not be used. This stems, among other things, from the fact that in this scenario addressing schemes vary and some of them are non-IP. This paper presents the architecture and implementation of a new messaging system. We make use of disruption-tolerant network concepts to enable messaging over heterogeneous links. We provide reliable and unreliable transport, message priorities, and load balancing over multiple interfaces. The application programming interface, the way messaging applications are built, is the familiar email system.

Analysis and implementation of the virtual network system

Messaging applications want to use different communication networks. But the unfortunate state of affairs is that applications need to use several different application programming interfaces (APIs) and to design protocols on how and when to use a specific communication network(s). This is troublesome, error-prone and APIs vary a lot; applications want to use just one API but get the benefit of several communications networks. In this paper we detail, implement and test in real field tests a virtual network system (VNS). We argue why messaging applications should use and benefit from VNS. The VNS is a middleware solution that enables seamless usage of different networks. Netlink Next Generation (NLNG) protocol is a practical implementation of VNS and we elaborate on its features, design choices and problems faced. The NLNG protocol has its origins in the Linux Netlink and VNS concept is a middleware, thus we provide a comparison between these previous works and our work. The VNS system and NLNG protocol have already been tested with several applications, e.g., mail clients, tracking and command softwares, and network interfaces, e.g., IP, VHF, HF, GSM SMS and TETRA SDS.

Mobile short data services as a carrier for message communications

Mobile short data services are commonly available on most mobile communication devices, but are mostly used for plain text messaging. In this paper we investigate the use of different mobile services for use with unified messaging platform. The services analyzed are the ubiquitous GSM/UMTS branch cellular mobile network, TETRA professional mobile radio (PMR) network and Iridium low earth orbit (LEO) satellite phone network. Individually each of these have various strengths and weaknesses, so the task is to optimize the system to concentrate on the strengths of each network. Contribution of this paper is a robust control scheme for mobile modems, a simple model for integrating them to a messaging platform and performance evaluation of GSM, TETRA and Iridium message services. This work can be used in emergency management in an always best connected manner.

Subscriber Aware Fair Routing in wireless mesh networks

Multi-radio wireless mesh networks (WMN) is a feasible choice for several applications, as routers with multiple network interface cards (NICs) have become cheaper. Placement of multiple NICs on each router can significantly improve the network performance if channels are assigned wisely. This is due to the fact, that by using multiple non-interfering channels wireless interference is diminished.

A model for usability testing in challenging environments

Remote software usability testing has been studied for over two decades. Yet, many of the existing testing methods are not ideal for field testing in challenging environments typical to military and emergency operations and contexts. In this paper we introduce a model and a messaging framework that allow remote usability tests to be run easily in the real work context of the users. We also introduce a proof-of-concept implementation of the model and show how the model can be integrated to an existing user interface of a military communication system. To verify our model, we pilot the test set-up on real end users of the system.

XCD: An XML-based configuration description for embedded systems

We are surrounded by different smart networked embedded devices that are running software dedicated to specific tasks. Many of these devices have no displays or user interfaces. To control and configure these devices remotely over network, instead of running factory-set static settings, devices need to be able to publish their parameters to a remote user interface of the system. In modular systems, the components of the system also need to communicate with each other to ensure interoperability. In this paper we introduce eXtensible Configuration Description (XCD) that defines the characteristics of a device or system component as variables and their interrelationships in a unified format. XCD allows devices to exchange information about their configuration with other devices (machine-to-machine, M2M), or to publish the configuration to a generic remote user interface (UI) of the system. The paper describes the structure of XCD and shows two use cases where the description is used to configure an embedded system. We also show how the generic nature of XCD enables us to render the same XCD description of a device in two different user interfaces.

Hierarchical link-state routing in disruption-tolerant networks

Disruption-Tolerant Networking (DTN) is the technological tool for operating in networks that while performant are intermittently available and may lack end-to-end connectivity. Routing in DTN networks is an open research problem and there has been interest in tying DTN resiliency to Mobile Ad-hoc Networks (MANET) performance. Using the Multi Interface Communications Software (MICS) framework, we explore use of a linkstate routing protocol in DTN environment. We detail the improvements done to the routing protocol to enhance operation in hierarchical network topologies.