• Journal of the Korean Chemical Society
• /
• v.56 no.5
• /
• pp.571-576
• /
• 2012

A sol-gel derived carbon composite electrodes (CCEs) were fabricated by mixing horseradish peroxidase (HRP), sol of tetraethoxysilane (TESO), and graphite powder. The HRP solution was added to the sol solution of TEOS, and then graphite powder was added to this mixture. The resulting carbon ceramic network effectively encapsulated HRP and shows a catalytic reduction starting at -0.2 V for $H_2O_2$. The optimum conditions for $H_2O_2$determination have been characterized with respect to the enzyme loading ratio and pH. The linear range and detection limit of $H_2O_2$ detection were from 0.2 mM to 2.2 mM and 0.035 mM, respectively. The common electroactive interferences such as ascorbic acid, acetaminophene, and uric acid were not affected upon the response to $H_2O_2$ at the HRP biosensor due to low detection potential.

• Journal of KIISE
• /
• v.42 no.11
• /
• pp.1430-1440
• /
• 2015

In contrast with battery-based wireless sensor networks (WSNs), solar-powered WSNs can operate for a longtime assuming that there is no hardware fault. Meanwhile, a mobile sink can save the energy consumption of WSN, but its ineffective movement may incur so much energy waste of not only itself but also an entire network. To solve this problem, many approaches, in which a mobile sink visits only on clustering-head nodes, have been proposed. But, the clustering scheme also has its own problems such as energy imbalance and data instability. In this study, therefore, a cluster-based energy-aware data-sharing scheme (CE-DSS) is proposed to effectively support a mobile sink in a solar-powered WSN. By utilizing the redundant energy efficiently, CE-DSS shares the gathered data among cluster-heads, while minimizing the unexpected black-out time. The simulation results show that CE-DSS increases the data reliability as well as conserves the energy of the mobile sink.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.48 no.4
• /
• pp.40-46
• /
• 2011

Wireless Sensor Networks(WSNs) have shown a lot of good outcomes in providing a various functions depending on industrial expectations by deploying ad-hoc networking with helps of light loaded and battery powered sensor nodes. In particular, it is strongly requested to develop an algorithm of cross-layer control between 2-layer and 3-layer to deriver the sensing data from the end node to the sink node on time. In this paper, based on the above observation we have proposed an IEEE802.15.4 based self priority routing scheme under UC Berkely TinyOS platform. The proposed beacon based priority routing (BPR) algorithm scheme utilizes beacon periods in sending message with embedding the high priority data and thus provides high quality of service(QoS) in the given criteria. The performance measures are the packet Throughput, delivery, latency, total energy consumption. Simulation results under TinyOS Simulator(TOSSIM) have shown the proposed scheme outcome the conventional Ad hoc On-Demand Distance Vector(AODV) Routing.

• Polymer(Korea)
• /
• v.35 no.3
• /
• pp.216-222
• /
• 2011

A multi-walled carbon nanotube (MWNT) support with dual properties, an ionic property via tetra-amine and unpaired electrons via tri-amine, was prepared by radiation-induced graft polymerization of glycidyl methacrylate (GMA) and the subsequent amination of its epoxy group. The electrochemical microbial biosensor (EMB) was then fabricated by immobilization of a microbe (Alkaligenes spp.) onto the dual property-modified electrode, which was prepared with the mixture of the MWNT support and a $Nafion^{(R)}$ solution on a glass carbon (GC) electrode surface by a hand-casting method. The sensing range of the prepared EMB for phenol in a phosphate buffer solution was 0.005~7.0 mM. The total concentration of phenolic compounds in a commercial red wine was also determined using the EMB.

• Polymer(Korea)
• /
• v.33 no.1
• /
• pp.19-25
• /
• 2009

New polyelectrolytes derived from ionene-containing photocurable reactive oligomer (PIDM) were prepared for water-resistant humidity-sensitive membranes. The mixture of PIDM, hexamethylene dimethacrylate (HDM), pentaerythritol triacrylate dimer (SP1013), and photoinitiator was simultaneously coated on the sensor electrode with photoinitiated radical polymerization. The pretreatment of the substrates with vinyl-type silane-coupling reagent was performed for improving the water durability and stability of the sensors at high temperature and humidity. When the resistance dependences on the relative humidity of the crosslinked PIDMs were measured, it was found that the resistance varied three orders of magnitude between 20 and 90%RH, which was required for the humidity sensor operating at ambient humidity. Their hysteresis, temperature dependence, response time, water durability, and high temperature/humidity stabilities were measured and evaluated as a humidity-sensing membrane.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.5
• /
• pp.219-227
• /
• 2008

As found in research on constraint satisfaction problems, the choice of variable ordering heuristics is crucial for effective solving of constraint optimization problems. For the special problems such as energy-efficient clustering in heterogeneous wireless sensor networks, in which cluster heads have an inclination to be near a base station, we propose a new approach based on the static preferences variable orderings and provide a pnode heuristic algorithm for a specific application. The pnode algorithm selects the next variable with the highest Preference. In our problem, the preference becomes higher when the cluster heads are closer to the optimal region, which can be obtained a Priori due to the characteristic of the problem. Since cluster heads are the most dominant sources of Power consumption in the cluster-based sensor networks, we seek to minimize energy consumption by minimizing the maximum energy dissipation at each cluster heads as well as sensor nodes. Simulation results indicate that the proposed approach is more efficient than other methods for solving constraint optimization problems with static preferences.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.4
• /
• pp.553-559
• /
• 2020

Seaweed(Laver), Korea's largest export product, is currently focused on mass production due to the market situation in Korea. This naturally led to a decrease in the quality of seaweed. Therefore, in this paper, the present method was produced and tested by changing the way of adjusting the ratio of seaweed mixing, which was dependent on the user's sense and experience in the production of seaweed. In addition, I developed an embedded measurement system that can determine the concentration of a mixture of gold in real time based on primary image information obtained through an IR LED lamp that generates a light source and a photo sensor that detects concentration. By collecting and storing precise data in real time, it is easier to cope with the previous year's data in a work environment that is repeated every winter.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.161-161
• /
• 2020

최근 기후변화와 여름철 고온 등으로 인한 녹조현상, 화학물질 및 유류 유출 등 화학사고로 인한 하천의 수질오염과 관련된 사회적 관심이 높아지고 있다. 특히, 화학사고로 인한 유해화학물질 유출은 인체에 접촉 시 악영향을 끼치며, 대기·수질·토양을 오염시키고 주변 농작물의 변색이나 괴사를 유발하는 등의 피해를 야기하기 때문에 적절한 조치와 대응이 필요하다. 환경부에서는 유해화학물질 유출사고로 인한 국민건강 및 환경상의 위해를 예방하기 위해 화학물질관리법과 화학물질 등록 및 평가에 관한 법률을 제정하여 유해화학물질을 관리하고 화학사고에 대응하고 있다. 그러나, 화학사고 발생 시 공장 인근의 먼지, 악취 등을 감시하기 위해 현장인력에 의존하거나 화학물질의 유출이 우려되는 곳에 제한적으로 검출센서를 설치해 사고를 감시하고 있어 검출센서 미설치 지역에 대한 능동적 탐지가 어렵고, 화학물질의 공간적 분포 탐지가 불가능하여 초동 대응에 한계가 있다. 한편 최근 초분광 영상을 활용하여 물질 고유의 분광특성을 분석함으로써 토지피복, 식생, 수질 등의 식별에 활용되고 있다. 따라서 초분광 센서를 활용한 화학물질 감지 가능성도 보여주고 있지만, 초분광 센서를 활용한 하천의 화학물질 감지를 위한 연구는 미비한 실정이다. 이에 본 연구에서는 유해화학물질 18종을 대상으로 초분광 영상을 이용한 상호 구분이 가능한 지 확인하고자 해당 유해화학물질의 초분광 영상을 촬영하여 분광라이브러리를 구축하였다. 또한 물질별 특성을 보이는 분광밴드의 범위를 지정해 특성 분광라이브러리를 구축하였으며, 해당 과정에 대한 표준 및 절차를 제시하였다. 본 연구에서 제시한 절차에 따라 18종의 유해화학물질 분광라이브러리와 특성 분광라이브러리를 구축한 결과, 유해화학물질의 식별 가능성을 확인하였다. 향후 연구를 통해 유해화학물질 분광라이브러리 데이터베이스를 확대하고, 실시간 모니터링에 적용할 경우 신속한 화학사고 발생여부 감지 및 대응에 활용할 수 있을 것으로 사료된다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.112-113
• /
• 2021

하천으로 유입되는 오염물질은 유수의 흐름에 따라 이송되며 혼합된다. 이러한 오염물질의 해석을 위해서는 확산 또는 분산계수 산정이 필요하다. 오염물질의 거동과 관련된 실험적 연구는 방사선 동위원소와 형광성 물질을 이용하여 수행되어 왔으나, 추적자 실험은 많은 비용 및 인력을 요하며, 고정식으로 설치한 계측장비로부터 수집한 시계열 농도자료만을 이용하여 분석하기 때문에 공간적 분포에 대한 자료 취득은 어렵다는 한계가 있다. 하천의 오염물질을 모니터링하기 위해서는 공간을 이동하는 입자의 관점에서 물리량을 표현하는 Lagrangian 방식보다 특정 위치에서 물리량 변화를 표현하는 Eulerian 방식이 적합하다. 그러나 드론을 활용한 하천원격탐사 연구의 대부분은 이동식 플랫폼으로 활용되어 특정 시간에 공간적 분광특성의 분포 파악이 한정적이며, 동일 지점에서 분광특성의 시간적 변화를 파악할 수 없다. 따라서 본 연구에서는 기존의 면단위를 측정하는 이동식 플랫폼의 한계를 극복하고 하천 모니터링에 적합한 Eulerian 방식을 적용하기 위하여 CCTV 형태의 고정식 초분광촬영 플랫폼을 도입하였다. 본 연구에서는 하천으로 유입되는 오염물질의 거동을 분석하기 위하여 자연하천에서 형광성물질인 Rhodamine WT를 이용하여 추적자 실험을 수행하였으며, 접촉식 센서를 활용한 농도측정과 동시에 드론과 초분광센서를 활용하여 CCTV 형태의 고정식 초분광영상을 획득하였다. 실험결과 도출된 전통적인 방식의 분산계수 산정과 시공간 초분광영상을 활용한 분산계수 산정을 비교하여 오염물질 거동 분석에 초분광영상 활용의 가능성을 검토하였다. 본 연구에서 제시한 드론기반 시공간 초분광영상 기법을 교량이나 기타 하천구조물에 초분광 센서를 설치하여 CCTV형식으로 활용할 경우, 공단이나 하·폐수 처리장 등의 점오염원이 밀집해 있는 지역에 직접 설치하여 화학사고의 감지 및 오염물질의 유출 확인 및 조류, 부유사 등의 다양한 수질항목의 농도 변화 감지가 가능하고, 수심변화 감지로 장기적으로 활용할 경우 특정 지점에서의 하상변동 조사가 가능하다. 또한, 오염물질의 유출 사고 발생 등의 사람이 직접 접근이 불가능한 지역에 드론을 활용하여 초분광센서를 이용한 오염물질 감지가 가능할 것으로 판단된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.313-316
• /
• 2021

In the IoT(IoT: Internet of Things) environment, network configuration is essential to collect data generated from objects. Various communication methods are used to process data of objects, and wireless communication methods such as Bluetooth and WiFi are mainly used. In order to collect data of objects, a communication module must be installed to collect data generated from sensors or edge devices in real time. And in order to deliver data to the database, a software architecture must be configured. Data generated from objects can be stored and managed in a database in real time, and data necessary for industrial safety can be extracted and utilized for industrial safety service applications. In this paper, a network environment was constructed using a LoRa(LoRa: Long Range) gateway to collect object data, and a client/server data collection model was designed to collect object data transmitted from the LoRa module. In order to secure the resources necessary for data collection and storage management without data leakage, data collection should be possible in real time. As an application service, location data required for industrial safety can be stored and managed in a database in real time.