Sungwon Lee

Sungwon Lee
Kyungpook National University | KNU · School of Computer Science and Engineering

About

73
Publications
8,090
Reads
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1,265
Citations
Citations since 2016
17 Research Items
818 Citations
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
Introduction

Publications

Publications (73)
Article
Full-text available
In underwater wireless sensor networks (UWSN), acoustic communication naturally introduces challenges such as long propagation delay and high packet loss. The flooding-based routing protocol can address these challenges with its multipath characteristics. As in flooding-based routing, due to multipath propagation mechanism, not only DATA but also A...
Article
Full-text available
The principle of Smart Cities is the interconnection of services, based on a network of Internet of Things (IoT) devices. As the number of IoT devices continue to grow, the demand to organize and maintain the IoT applications is increased. Therefore, the solutions for smart city should have the ability to efficiently utilize the resources and their...
Conference Paper
Full-text available
For providing Internet service to underwater IoT nodes, it is necessary to divide the IPv6 packets appropriately according to appropriate MTU size. 6LoWPAN adaptation layer defined by IETF is able to support the address auto-configuration, header compression and so on. In particular, 6LoWPAN defines two configuration methods. In route-over configur...
Article
Full-text available
Unlike terrestrial environment, the underwater environment possess additional and complicated challenges for wireless communication. For the underwater wireless communication, traditional radio wave communication is not feasible due to high channel fading and packet loss experienced high frequency communication that also reduces the communication r...
Conference Paper
Full-text available
Internet of Underwater Things (IoUT)¹ is a network of networks mostly comprising of Underwater Wireless Sensor Networks (UWSNs) of underwater objects. These sensing nodes provide various services such as disaster prevention and management, tactical surveillance and environmental monitoring. Due to the underwater environmental constraints, these sen...
Conference Paper
The use of bicycles, Segway, Ninebot, and etc. has been rapidly increasing due to the development of personal mobility and technological shift. On the other hand, due to the extensive use of headphones, and smart phones while walking on the road and riding a bicycle, the probability of collisions between pedestrian and bicycle increases. In this re...
Article
Full-text available
In underwater wireless sensor networks (UWSNs), not only data packets but also sensor nodes can be lost due to ocean current, running out of battery and etc. Among various routing protocols, Routing Protocol for Low Power and Lossy Networks (RPL) is a promising routing protocol to overcome this problem since it provides multiple upward path establi...
Conference Paper
In IoT (Internet of Things) networks, RPL (IPv6 Routing protocol for Low Power and Lossy Networks) is preferred for reducing routing overhead. In RPL, a node selects one parent node which includes the lowest routing metric among its neighbors and the other neighbors are stored as immediate successors. If the selected parent node is lost, the node s...
Conference Paper
From the decades ago, the ITS (Intelligent Traffic System) became one of the major research field. In order to save human lives, ITS safety applications collect various information from neighboring vehicles. For the ITS safety application, each vehicle periodically broadcasts beacon messages in order to update the information to the neighbors. Howe...
Article
Synthetic natural gas(SNG), acquired from coal, is regarded as an alternative to natural gas since a rise in natural gas due to high oil price can be coped with it. In the present study, 11-liter heavy duty compressed natural gas(CNG) engine was employed in order to examine the combustion and emission characteristics of SNG. The simulated SNG, made...
Article
Full-text available
Recently, as interest in IoT (Internet of Things) increase, research and standardization of a new protocol which reflects the characteristics of IoT has progressed. Among them, RPL(IPv6 for Low-Power Lossy Network) is a standardized routing protocol for IoT. RPL utilizes DIO (DODAG Information Object) messages which is flooded from the sink node to...
Conference Paper
For underwater wireless acoustic networks (UWANs), the Directional Flooding-based Routing (DFR) protocol determines the flooding area according to the quality of the link between a node and its neighbors. However, since the sending node in the originating DFR calculates the node's link quality by considering all of its neighbors equally, those neig...
Conference Paper
Nowadays, wide variety of devices have been considered for IoT (Internet of Things) research. In this paper, we introduce IPv6 packet transmission using NFC (Near Field Communication) devices. We propose an IPv6 adaptation layer that modi?es the existing standard to successfully operate over NFC devices with no impediment to the existing standard....
Article
Because of the global increase in the consumption of low-calorie natural gas, and increasing awareness of the mid-to long-term problem with the decrease in the calorific value of natural gas, actions are needed to minimize the problems with gas appliances. Most natural gas engines for small distributed cogeneration systems operate with a lean fuel/...
Article
In order to meet the current emission regulations (EURO-6), it is necessary to significantly reduce CH4 and NOx emissions. This study investigated the effect of a reduction in the valve overlap on the combustion and emission characteristics of a hydrogen-compressed natural gas engine under a part-load operating condition. The combustion and emissio...
Article
A number of routing protocols have been proposed for underwater wireless sensor networks (UWSNs). However, most of their routing protocols do not take into account the environmental information like water depth since the shallow and deep water have different characteristics. In this article, we present an environment-aware routing protocol (named E...
Article
Post-polymerization radical bromination of a nanostructured poly(ionic liquid) that selectively introduces a reactive bromo-group onto the polyalkylthiophene backbone is described. Raman and FT-IR spectroscopy proves that the bromine is successfully introduced at the 3-methyl position of the thiophene and that the molecular structure of the polymer...
Article
In typical end-to-end recovery protocols, an ACK segment is delivered to a source node over a single path. ACK loss requires the source to retransmit the corresponding data packet. However, in underwater wireless sensor networks which prefer flooding-based routing protocols, the source node has redundant chances to receive the ACK segment since mul...
Article
Full-text available
In order to increase network lifetime, duty-cycle MAC protocols which can reduce energy consumption caused by idle listening is proposed for WSNs. In common duty-cycle MAC protocols, each sensor node calculates its duty-cycle interval based on the current amount of residual energy. However, in WSNs with the capability of energy harvesting, existing...
Article
SUMMARY Recently, underwater wireless sensor networks (UWSNs) have attracted much research attention to support various applications for pollution monitoring, tsunami warnings, offshore exploration, tactical surveillance, etc. However, because of the peculiar characteristics of UWSNs, designing communication protocols for UWSNs is a challenging tas...
Article
Full-text available
Underwater acoustic sensor networks (UASNs) consist of remotely deployed sensor nodes under sea or other water environments. Due to the extreme limitations faced by radio signals under water, acoustic channels are utilized for communication in such networks. However, UASNs are challenged by the characteristics of underwater acoustic channels such a...
Article
Underwater Wireless Sensor Networks (UWSNs) have distinctive characteristics due to the use of acoustic signals as its physical medium for communications, including high propagation delay, limited bandwidth and high error rates. Hence, designing communication protocols, particularly, an efficient routing protocol for UWSNs is a challenging issue. R...
Conference Paper
In a Wi-Fi Direct network, a single battery-powered mobile device called group owner (GO) helps other mobile devices communicate each other without relying on a pre-existing infrastructure such as base stations. Hence, the Wi-Fi Direct defines two power saving schemes for the energy efficiency of GO, called opportunistic power save (OPS) and notice...
Conference Paper
The WAVE standard supports reliable safety message transmission to avoid the vehicle-to-vehicle (V2V) accidents. However, it overlooks a vehicle-to-pedestrian (V2P) accident since we do not have any support to exchange the safety messages between the pedestrians and vehicles. Nowadays, the pedestrians will be able to exchange the safety messages wi...
Article
Full-text available
Natural gas vehicle engines are preferred over diesel engines because they release significantly lower amounts of nitrogen oxides (NOx) and carbon dioxide emissions. Hydrogen-compressed natural gas (HCNG) technology is a promising alternative to that used in conventional compressed natural gas engines because hydrogen possesses stable lean combusti...
Article
To counteract the harmful effects of vehicle emissions on humans and the environment, such as global warming due to greenhouse gases, there is a focus on gaseous fuels as an alternative energy source of transportation. Heavy-duty natural gas vehicles are widely used to improve the air quality of urban areas in Korea because natural gas has the adva...
Article
Full-text available
Nowadays, wireless sensor networks (WSNs) are used in a variety of areas. However, it is difficult to efficiently manage a large number of sensor nodes and their sensing data owing to the limitations of WSNs. Particularly, in agricultural applications, a WSN installed in a specific region is used for multiple services (i.e., greenhouse environment...
Article
Full-text available
In underwater wireless sensor networks (UWSNs), flooding-based routing protocols are preferred due to their capability of reducing the routing overhead in terms of no need of path setup and maintenance. In addition to routing, a transport protocol should be developed to recover lost DATA segments in loss-prone UWSNs. In particular, due to long prop...
Article
Hydrogen-compressed natural gas blend (HCNG) engines can extend the lean burn limit because of the wide flammability range of hydrogen. Lean combustion helps facilitate high efficiency and fundamentally reduces NOx emission. Increasing the compression ratio (CR) of an HCNG engine was reported to improve its thermal efficiency. However, the high ris...
Conference Paper
Full-text available
Underwater acoustic sensor networks (UASN) significantly differ from the terrestrial wireless sensor networks (WSNs) due to the nature of acoustic channels in underwater environments. In contrast to the radio channels, acoustic channels suffer from lower propagation delay and limited bandwidth. Under such conditions, medium access layer (MAC) overh...
Article
In this, three types of natural gas were employed to investigate the effect of low-calorific natural gas on the performance of and emissions from a heavy-duty CNG engine. The performance and emission characteristics were analyzed by conducting a full-load test, WHSC mode test, and WHTC mode test. The results showed that the torque of low-calorific...
Chapter
The Intelligent Transportation System (ITS) can be considered the most representative example of Machine-to-Machine (M2M) applications in a standardization and commercial market. To support the applications, utilizing multiple network interfaces and providing appropriate network connectivity to them are the key issues in order to meet different net...
Article
Full-text available
Hydrogen-natural gas blends(HCNG) engine is optimizing technology of performance and emission characteristics with use of hydrogen's fast flame speed and wide flammability limit. As lean-burn limit is extended, the improvement in thermal efficiency and harmful emissions can be achieved. However, the extension of lean-burn limit under a wide open th...
Conference Paper
In underwater wireless sensor networks (UWSNs), flooding-based routing protocols are preferred for reducing routing overhead. In addition to routing, a transport protocol should operate to provide the end-to-end reliability in USWNs. Fortunately, the Fast Retransmit technique can be exploited for fast retransmissions of lost DATA segments. However,...
Article
Heavy-duty natural-gas vehicles contribute towards environmental improvement in the air quality of downtown areas because the particulate matter emissions are quite low and lean combustion facilitates improvement in the efficiency and reduction in the harmful emissions. However, because stronger emission regulations such as Euro VI cannot be satisf...
Conference Paper
In Underwater Wireless Sensor Networks (UWSNs), many flooding-based routing protocols have been proposed because of their low routing overhead. However, they rely on the location information and current underwater localization techniques cannot provide the exact location information to all sensor node. Therefore, we need a new routing protocol whic...
Article
Full-text available
Compression ratio is an important factor affecting engine performance and emission characteristics since thermal efficiency of spark ignition engine can be theoretically improved by increasing compression ratio. In order to evaluate the effect of compression ratio change in HCNG engine, natural gas engine was employed using HCNG30 (CNG 70 vol%, hyd...
Article
Compressed natural gas (CNG) buses were adopted in urban areas as a promising alternative to diesel buses, which emitted plenty of harmful emissions. Although CNG can meet the current emission standards, satisfying the requirements of the next EURO-VI emission regulation without an additional peripheral device may be impossible. The use of a hydrog...
Article
The wide range of hydrogen's flammable limits enables ultra-lean combustion. A lean burn reduces the combustion temperature, increases thermal efficiency, and reduces knock, which is a serious problem in a spark ignition (SI) engine. The anti-knock improvement from hydrogen addition makes it feasible to increase the compression ratio (CR) and furth...
Article
Full-text available
CNG buses has contributed to improve air quality in cities. But it is difficult to meet the next emission regulations such as EURO-VI without the help of additional post-processing device. Hydorgen has higher flame speed and lower combustion temperature that make it thermal efficiency increase with leaner operation. Using hydrogen natural gas blend...
Article
Full-text available
As emission regulation for vehicle has been reinforced, many researches carried out for HCNG(hydrogen-natural gas blends) fuel to the conventional compressed natural gas (CNG) engine. However, abnormal combustion such as backfire, pre-ignition or knocking can be caused due to high combustion speed of hydrogen and it can result in over heating of en...
Article
The thermoreversible mechanical properties of a non-ionic polymer, lipid-based complex fluid were investigated by oscillatory and steady shear rheology, and analyzed in the context of mesophase architecture and polymer–water interactions. The sol phase (G″>G′) is observed at lower temperatures (5–17 oC) than the gel phase (G′>G″; 20–50 oC) and is d...
Conference Paper
In underwater wireless sensor networks, asynchronous duty-cycle MAC protocols and gradient based routing protocols can be used in order to extend network lifetime and provide network scalability, respectively. However, in asynchronous duty-cycle MAC protocols, the advertisement message which is essential in gradient based routing protocols cannot b...
Article
Glucose oxidase (GOx) adsorbed on an ionic liquid-derived polymer containing internally organized columns of Au nanoparticles exhibits direct electron transfer and bioelectrocatalytic properties towards the oxidation of glucose. The cationic poly(ionic liquid) provides an ideal substrate for the electrostatic immobilization of GOx. The encapsulated...
Article
Combined rheology (oscillatory and steady shear) and SAXS studies reveal details on the temperature-dependent, reversible mechanical properties of nonionic polymer, lipid-based complex fluids. Compositions prepared by introduction of the polymer as either a lipid conjugate or a triblock copolymer form an elastic gel as the temperature is increased...
Article
This paper proposes a novel mobility management scheme to support the mobility of legacy clients in wireless mesh networks. In order to provide compatibility with the IEEE 802.11s standard, methods for movement detection and new information propagation are implemented using primitives defined in the IEEE 802.11s proxy protocol. We verify that our p...
Article
In Wireless Mesh Networks (WMNs), the mobility management for mesh clients is one of the most challenging issues since they need to be provided with continuous network access service, regardless of their movements. However, the IEEE 802.11s, standard protocol for layer-2 WMNs, overlooks mobility management, which can disturb the smooth operation of...
Chapter
Recently, Underwater Wireless Sensor Networks (UWSNs) have attracted much research attention from both academia and industry, in order to explore the vast underwater environment. However, designing network protocols is challenging in UWSNs since UWSNs have peculiar characteristics of large propagation delay, high error rate, low bandwidth and limit...
Conference Paper
Underwater wireless sensor networks (UWSNs) suffers from high bit error rate, low bandwidth, long and variable propagation delay, etc. In these networks, providing reliability of packet transmissions is an important issue. However, with typical end-to-end acknowledgement methods, the networks experience an ACK explosion problem which leads to wasti...
Conference Paper
In Underwater Wireless Sensor Networks (UWSNs), developing an energy efficient routing protocol is a challenge due to the peculiar characteristics of UWSNs. In this paper, we therefore propose an energy-efficient routing protocol, called ERP<sup>2</sup>R (Energy-efficient Routing Protocol based on Physical distance and Residual energy). ERP<sup>2</...
Article
In this work we describe the synthesis, fabrication and characterization of a gold nanoparticle - ionic liquid-derived polymer composite for conversion of biofuels into electricity. Glucose oxidase (GOx) electrostatically adsorbed on an ionic liquid-derived polymer containing internally organized columns of Au nanoparticles exhibits bioelectrocatal...
Article
Underwater wireless sensor networks (UWSNs) suffers from high bit error rate, low bandwidth, long and variable propagation delay, etc. In these networks, providing reliability of packet transmissions is an important issue. However, with typical end-to-end acknowledgement methods, the networks experience an ACK explosion problem which leads to wasti...
Article
Thermal free radical polymerization of a self-assembled, bifunctional imidazolium-based ionic liquid (IL) monomer bearing both vinyl and thienyl groups is reported. FT-IR spectroscopy proves that the polymerization occurs through both the vinyl and thienyl groups. The polymer is resistant to swelling in water and common organic solvents. The as-syn...
Conference Paper
Communications in underwater wireless sensor networks have a lot of limitations as compared to those in terrestrial sensor networks. In wireless sensor networks, a routing protocol finds a path between the source and sink nodes according to a routing metric. The hop count is the most widely used routing metric, however, it cannot reflect the qualit...
Article
The preparation and polymerization of a bifunctional imidazolium-based ionic liquid (IL) monomer that incorporates both a vinyl group and a thiophene moiety is reported. Potentiodynamic electropolymerization of the monomer produces an optically birefringent polymer film that strongly adheres to the electrode surface. Fourier transform IR spectrosco...
Article
M. A. Firestone et al. present a polymer that incorporates an electronic component with an ionic liquid and produces a mixed ionic and electronic conductor on page 2063. Electropolymerization of a bifunctional imidazolium-based ionic liquid monomer incorporating both vinyl and thiophene groups yields a liquid-crystalline polymer that adopts an inte...
Article
In this work we describe the single-step synthesis of a robust, self-supporting gold nanoparticle - ionic liquid-derived polymer composite and evaluate its transport properties. Specifically, a gold nanoparticle-containing ionic liquid-derived polymer is synthesized in a single step by UV irradiation of a metal ion precursor-doped, self-assembled d...
Article
The tunability of the chemical composition of ionic liquids (ILs), achieved by pairing various organic cations with numerous anions, allows for fine control of their physicochemical properties and has been widely used for the adjustment of the IL solvent characteristics. Exploitation of IL structural modularity coupled with chemical modification of...
Article
The transport properties of self-supporting Au nanoparticle-ionic liquid-derived polymer composites were characterized. Topographic AFM images confirm the perforated lamellar composite architecture determined by small-angle X-ray scattering (SAXS) and further show that the in situ synthesized Au nanoparticles are localized within the hydrophilic (w...
Article
A significant and frequently encountered challenge when making an electrical connection to a protein is that its electron-transfer sites are buried within the polypeptide matrix and thus, are not readily accessible to bulk metal electrodes. A further complicating factor is that inorganic (i.e., metallic) electrodes are often incompatible with biolo...
Article
Preparation and polymerization of methylimidazolium-based ionic liquids (ILs) that incorporate a thiophene moiety at the terminus of a C10 alkyl chain are described. Both a bromide and nitrate salt of the amphiphilic thiophene IL self-assembles in water (albeit the nitrate to a lesser extent), adopting columnar mesophases. Polarized optical microsc...

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