• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.4
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• pp.214-217
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• 2017

An IGBT (insulated gate bipolar transistor) device has an excellent current-conducting capability. It has been widely employed as a switching device to use in power supplies, converters, solar inverters, and household appliances or the like, designed to handle high power. The aim with IGBT is to meet the requirements for use in ideal power semiconductor devices with a high breakdown voltage, an on-state voltage drop, a high switching speed, and high reliability for power-device applications. In general, the concentration of the drift region decreases when the breakdown voltage increases, but the on-resistance and other characteristics should be reduced to improve the breakdown voltage and on-state voltage drop characteristics by optimizing the design and structure changes. In this paper, using the T-CAD, we designed the NPT-IGBT (non punch-through IGBT) and FS-IGBT (field stop IGBT) and analyzed the electrical characteristics of those devices. Our analysis of the electrical characteristics showed that the FS-IGBT was superior to the NPT-IGBT in terms of the on-state voltage drop.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.99-104
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• 2006

In this paper, the conventional 2 dimensional metamaterial structure has degeneration of shielding characteristic in cross polarization effect. The proposed 3-D resonator is designed for reduction of cross polarization effect. The proposed 3-D resonator using LTCC consists of 2-D parallel resonators on X-axis, Y-axis and Z-axis. The 2-D parallel resonator consists of two plate and one via. When the co-polarization electric filed is excited, the resonance frequency of 3-D resonator is 5.024GHz. The stop bandwidth is 19MHz. When the cross-polarization electric field is excited, the resonance frequency of 3-D resonator is 4.825GHz. The stop bandwidth is 19MHz. The proposed 3-D resonator achieve reduction of cross-polarization effect. The concrete consists of proposed 3-D resonator and absorbtion materials. The concrete will be applied for reduction or interference signal of ETCS(Electric Toll collection system).

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.4
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• pp.482-492
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• 2015

Objectives: Exposure Assessment for workplace hazards where the exposure level is below occupational exposure limits(OELs) has been performed without considering either the degrees of risk or exposure levels and has failed to lead to intervention in many cases. The objective of this study was to suggest and test an application framework for risk assessment methodology under the current exposure assessment system in Korea. Materials: First, we investigated the exposure assessment systems in Korea and other countries. To adopt some risk assessment techniques, we also analyzed risk assessment systems and compared them to exposure assessment systems. A few suggestions were made. We held a public hearing during an industrial hygiene conference and took surveys using a questionnaire. Results: The first suggestion was to implement the risk assessment and exposure assessment through a "one-stop" system. In that case, one expected question would be who has been doing the jobs so far. In most cases, industrial hygiene consulting services or laboratories have been performing exposure assessment for business owners. Business owners are required to perform risk assessment. As two different groups of people will be required to implement two things in a one-stop system, they need to share information. As an information vehicle to share information, commonly filed survey checklists were suggested. The second suggestion was to categorize exposure level into four groups instead of the current binary divisions based on OELs. In the risk assessment system, exposure level is divided into four groups utilizing the cut-points of 10%, 50%, and 100% of OELs. The same schema can be adopted in the exposure assessment system and different levels of requirements can be assigned for each group. The third suggestion was regarding the regulation system. To provide the suggestions some thrust toward being implemented in the field, changes should be made in the legal system. Two different types of new exposure assessment result reporting forms were suggested. Some investigations such as an ergonomic survey are officially accepted as risk assessment under the current legal system. A few items were suggested to be included in the exposure assessment result reporting to be accepted as risk assessment. A pilot study in two small factories was performed and pointed out the strengths and weakness of our suggestions. Conclusions: Discussions and studies on the improvement of the exposure assessment system have been held for decades and no tangible changes have yet been made. We hope this result can help realize healthy lives for workers in Korea.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.715-723
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• 2013

Following the social consensus for the need to stop sexual violence, the government has amended juvenile sex protection laws to impose fees on education practitioners who do not report sexual crimes against women, and amended the 'domestic violence prevention and victim protection laws' (2012. 2) so that the police can investigate on site. However, regardless of these wide efforts, the reality is that sexual crimes against the socially weak do not seem to be dwindling, raising concerns of the effectiveness of such amendments. Generally sexual crimes are hard to prove, and even if reports are filed, most cases are dropped with non-prosecution disposition. Victims are usually limited to women and children and this leads to secondary victims. As this thesis states, developed countries have a more systematic protection methods than our country. Therefore, the purpose of this thesis lies on the construction of public safety infrastructure for the protection of sexual abuse victims (enhancing safety protocols with related organizations, implementing a bill of rights for the victims, prevention-centered police education, amendments to current law) to limit human rights violations and criminal injuries.

• The Korean Journal of Emergency Medical Services
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• v.13 no.3
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• pp.77-90
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• 2009

Civil complaints and lawsuits filed in the process of providing emergency medical service include fall accident on the way of carrying the patient, transfer consent, refusal and rejection of rescue request, range and behavior restriction of emergency medical technicians, false registry of logbook, neglect of duty and emergency patient, and violation of traffic laws on the way of dispatch to the scene of accident. This study suggested the measures by cases as follows. 1. The accidents on the way of carrying a patient could be divided into fall of patient and fall by paramedic's mistake. In the former case, damages caused by the ambulance's shaking must be notified to the patient and guardian and recommended to fasten seat belt, in the latter case, the plan of patient's posture, route of transport, rescue and equipments should be comfirmed before fixing the patient. 2. Transfer consent must be made as implied when the patient is unconscious under delusion and was not able to consent physically, and paramedic must take an action by his judgment and record details of services on logbook. 3. When a patient refused to transfer, get 'confirmation of transfer refusal' and inform him of refusal. Paramedic should receive the signature. In addition, in case of refusal, transfer request should be made after hearing doctor's opinion and it should be notified to transfer request and superintendent of fire station after making 'confirmation of transfer refusal'. 4. Emergency medical technicians should perform their duties within the range of services prescribed by Article 41 of Law of Emergency Medical Service and Article 33 of Its Enforcement Regulations and shall not make announcement of death. In case of reporting the death to guardian, it is desirable to use record data like ECG results. 5. The best way to have protection from legal problems is making and keeping the exact records of accident and patient. Paramedic should not mention his subjective opinion about the accident-related matter. He must record correctly and keep the original medical records. 6. As emergency medical technicians are responsible for taking care of emergency patients, they must contact a briefing room when they meet a difficult situation suddenly due to vehicle stop or treatment of other patients and then must have support from neighboring hospital and other safety centers. 7. Since the ambulance operator is responsible for safety and careful driving of ambulance, he must be careful when he violates traffic regulations unavoidably. The operator should drive slowly below 10km/h at an intersection and pass it after getting way from general vehicles driving from all directions.